Software Engineering Vocabulary: 1,000 Key English Terms

bump

verb

Meaning

To raise a version number or update a dependency to a newer version, usually as a small change. Informally, also to raise a task's priority or remind people about a message.

Where you use it

Very common in commit messages and PR titles: 'Bump lodash from 4.17.20 to 4.17.21' (Dependabot writes these automatically) or 'bump the version to 2.1.0'. In team chat, 'just bumping this' means reminding everyone about an unanswered message.

Examples

1. Bump the version to 1.4.0 before you tag the release.

2. Just bumping this: could someone review my PR today?

Common phrases

bump the version · bump a dependency · version bump · just bumping this

domain name

noun

Meaning

The readable address of a website, such as example.com, which people type instead of a numeric IP address.

Where you use it

You register, buy, renew, transfer and point a domain name, usually through a registrar and for a yearly fee. In speech people mostly just say 'domain'.

Examples

1. Did anyone renew the domain name? The site is showing a parking page.

2. We bought the domain name last week, but it isn't pointing to our server yet.

Common phrases

register a domain name · renew a domain · custom domain · point a domain to

hosting

noun

Meaning

A service that keeps a website's files and code on servers connected to the internet, so that people can visit the site at any time.

Where you use it

Types include shared hosting, VPS, dedicated servers, cloud hosting and platforms such as Vercel or Netlify for front-end projects. People compare hosting providers and plans; the verb is 'host': 'We host it on AWS.'

Examples

1. The site goes down every evening; maybe it's time to change our hosting.

2. Shared hosting is fine for a small company website.

Common phrases

web hosting · shared hosting · hosting provider · cloud hosting · hosting plan

SSL certificate

noun

Meaning

A digital file installed on a server that proves the site's identity and lets the browser set up an encrypted HTTPS connection.

Where you use it

Certificates are issued by certificate authorities, including the free Let's Encrypt, and they expire, so they must be renewed. An expired certificate causes a full-page browser warning, a common cause of sudden outages.

Examples

1. Our SSL certificate expires next week. Is auto-renewal turned on?

2. The hosting panel installs a free SSL certificate for every domain.

Usage note

Modern sites actually use TLS, the newer protocol that replaced SSL, but most people and hosting panels still say 'SSL certificate'.

Common phrases

install an SSL certificate · renew a certificate · expired certificate · certificate authority · wildcard certificate

DNS

abbreviation

Meaning

Domain Name System: the internet's directory that translates domain names like example.com into the IP addresses of servers.

Where you use it

Developers edit DNS records, such as A, CNAME, MX and TXT, at their registrar or DNS provider. Changes can take time to spread, so people say 'wait for DNS to propagate'.

Examples

1. I updated the DNS records an hour ago, but some users still see the old site.

2. Add a CNAME record in your DNS settings to connect the custom domain.

Common phrases

DNS record · DNS propagation · DNS provider · update DNS settings

web server

noun

Meaning

Software, such as Nginx or Apache, that accepts HTTP requests and serves web pages and files; the term is also used for the machine that runs it.

Where you use it

Developers configure, restart and tune web servers, often placing Nginx in front of an application server as a reverse proxy. Typical tasks include redirects, compression and SSL settings.

Examples

1. The redirect is set up in the web server config, not in the app.

2. After you change the config, reload the web server.

Usage note

Nginx is pronounced 'engine x'.

Common phrases

configure a web server · reverse proxy · web server logs · restart the web server

cloud computing

noun

Meaning

Renting servers, storage, databases and other computing resources over the internet from a provider, instead of buying and running your own hardware.

Where you use it

The umbrella term for the whole field. In daily talk people simply say 'the cloud': 'we moved to the cloud', 'it runs in the cloud'. The formal 'cloud computing' appears in job titles, courses, reports and contracts.

Examples

1. Cloud computing lets a small startup launch in a week without buying a single server.

2. Our company started its move to cloud computing three years ago, and the old data center closes next month.

Common phrases

move to the cloud · cloud computing platform · cloud migration · in the cloud · cloud-based service

DevOps

noun

Meaning

A way of working in which developers and operations engineers share responsibility for building, releasing and running software, using automation to deliver changes quickly and safely.

Where you use it

Formed from 'development' and 'operations' and widely used since around 2009. It names a culture and set of practices, but in job ads it is also a role: DevOps engineer, DevOps team. Some people say DevOps should not be a separate team, only a way of working.

Examples

1. After we adopted DevOps practices, we went from one release a month to several a day.

2. We're hiring a DevOps engineer with Kubernetes and Terraform experience.

Common phrases

DevOps engineer · DevOps culture · DevOps practices · adopt DevOps · DevOps team

pipeline

noun

Meaning

An automated series of steps, such as building, testing and deploying, that runs every time code changes and stops if one step fails.

Where you use it

Engineers talk about pipelines all day: they run, pass, fail, turn green or red, and get stuck. A pipeline is made of stages and jobs. Common tools are GitHub Actions, GitLab CI and Jenkins.

Examples

1. The pipeline failed at the test stage, so nothing was deployed.

2. Can you re-run the pipeline? I think that error was just a network timeout.

Common phrases

CI/CD pipeline · run the pipeline · the pipeline failed · pipeline stage · deployment pipeline

container

noun

Meaning

A lightweight, isolated package that holds an application together with everything it needs to run, so it behaves the same on a laptop, a test server or in the cloud.

Where you use it

Containers share the host's operating system kernel, so they start in seconds and use less memory than virtual machines. You build, run, stop and restart containers; Docker is the best-known tool.

Examples

1. The container keeps restarting because the app crashes when the config file is missing.

2. Each microservice runs in its own container, so we can update them independently.

Usage note

In everyday English a container is any box or jar. In this field it always means a software container unless people are talking about shipping.

Common phrases

run a container · container image · container runtime · restart a container · containerized app

Docker

noun

Meaning

A widely used platform for building container images and running containers. It made containers popular after its release in 2013.

Where you use it

A product name, so it is written with a capital D, but in speech it is also used as a verb or adjective: 'dockerize the app', 'Docker image', 'Docker Compose file'. Many people use 'Docker' to mean containers in general.

Examples

1. Install Docker on your laptop and run the whole stack with one command.

2. We dockerized the legacy app so it can finally run on Kubernetes.

Common phrases

Docker image · Docker container · Docker Compose · dockerize an app · Docker Hub

Kubernetes

noun

Meaning

An open-source system that runs and manages containers across many machines: it starts them, restarts failed ones, spreads traffic and scales them up or down.

Where you use it

Originally designed at Google and released in 2014, now maintained by the Cloud Native Computing Foundation. Often written K8s (eight letters between K and s). Managed versions include Amazon EKS, Azure AKS and Google GKE.

Examples

1. Kubernetes restarted the crashed pods automatically, so users didn't notice anything.

2. Running Kubernetes yourself is a lot of work, so we switched to a managed cluster.

Usage note

The name comes from the Greek word for helmsman or pilot. Stress the third syllable: koo-ber-NET-eez.

Common phrases

Kubernetes cluster · deploy to Kubernetes · managed Kubernetes · Kubernetes manifest · run on Kubernetes

virtual machine

noun

Meaning

A complete computer, with its own operating system, that runs as software on a physical machine. One physical server can host many virtual machines at once.

Where you use it

Usually shortened to VM, said 'V-M'. You create, start, stop, resize and delete VMs. On AWS a VM is called an EC2 instance; Azure and Google Cloud use the term virtual machine or VM directly.

Examples

1. I created a small virtual machine to test the new Linux version before we upgrade.

2. Unlike a container, a virtual machine needs a few minutes to boot its full operating system.

Common phrases

create a virtual machine · VM size · spin up a VM · virtual machine image · guest operating system

instance

noun

Meaning

One running copy of a virtual server or service in the cloud. You choose its size, such as how many CPUs and how much memory it has, and pay while it runs.

Where you use it

Very common on AWS (EC2 instance, RDS instance) and in general talk: 'launch an instance', 'stop the instance', 'instance type'. It can also mean one copy of an application: 'we run three instances of the API'.

Examples

1. Please stop the test instances over the weekend so we don't pay for them.

2. We moved the database to a larger instance type with 64 GB of memory.

Usage note

In everyday English 'for instance' means 'for example', but in the cloud an instance is a running server, not an example.

Common phrases

launch an instance · instance type · stop an instance · EC2 instance · terminate an instance

cloud provider

noun

Meaning

A company that owns large data centers and rents computing, storage, networking and other services to customers over the internet.

Where you use it

The three largest are Amazon Web Services (AWS), Microsoft Azure and Google Cloud, sometimes called hyperscalers. Teams talk about choosing, switching and depending on a provider; 'vendor lock-in' is the worry of being stuck with one.

Examples

1. Our cloud provider had a problem in one region, and three of our services went down.

2. Before you pick a cloud provider, compare the prices of the services you'll actually use.

Common phrases

major cloud providers · switch cloud providers · vendor lock-in · public cloud provider

region

noun

Meaning

A geographic area where a cloud provider has a group of data centers, such as Frankfurt or Ireland. You choose the region where your resources run.

Where you use it

Each region has a code, such as eu-central-1 (AWS, Frankfurt). Teams choose a region for lower latency to users, lower price or to keep data in a certain country for legal reasons. Each region contains several availability zones.

Examples

1. We deploy to two regions, so a full outage in Frankfurt won't take us offline.

2. The bucket was created in the wrong region, which is why downloads were so slow.

Common phrases

choose a region · multi-region · region outage · deploy to a region · cross-region replication

environment

noun

Meaning

A separate copy of the whole system, with its own servers, settings and data, used for one purpose such as development, testing or serving real users.

Where you use it

Typical environments are dev, test, staging and production, often shortened to 'env'. Code moves from one environment to the next. 'Environment variables' are settings passed to an application from outside its code.

Examples

1. The bug only happens in the test environment, so it's probably a configuration problem.

2. Each developer can create a temporary environment for their branch.

Usage note

In general English 'environment' often means nature and the planet. In IT it almost always means a system setup, so 'çevre' is the wrong translation here.

Common phrases

test environment · production environment · environment variable · development environment · set up an environment

infrastructure as code

noun

Meaning

Managing servers, networks and other cloud resources by writing configuration files that tools read and apply, instead of clicking through a console by hand.

Where you use it

Shortened to IaC, said 'I-A-C'. The files live in Git, are reviewed in pull requests and applied by a pipeline. Popular tools are Terraform, OpenTofu, AWS CloudFormation, Pulumi and Ansible.

Examples

1. With infrastructure as code, we can rebuild the whole test environment in twenty minutes.

2. Nobody changes the firewall by hand anymore; it's all infrastructure as code and goes through review.

Common phrases

infrastructure as code tool · manage infrastructure as code · IaC template · IaC repository

IaaS

abbreviation

Meaning

Short for infrastructure as a service: renting basic building blocks such as virtual machines, disks and networks, while you manage the operating system and everything above it.

Where you use it

Usually compared with PaaS and SaaS to show how much the provider manages for you. Amazon EC2, Azure Virtual Machines and Google Compute Engine are typical IaaS products. Often said 'eye-az'.

Examples

1. With IaaS, the provider looks after the hardware, but patching the operating system is still our job.

2. We started on IaaS because we needed full control over the servers.

Common phrases

IaaS provider · IaaS offering · IaaS model · move to IaaS

PaaS

abbreviation

Meaning

Short for platform as a service: a ready-made platform where you only upload your code, and the provider runs the servers, operating system and runtime for you.

Where you use it

Pronounced like the word 'pass'. Heroku, Google App Engine, Azure App Service and AWS Elastic Beanstalk are common examples. PaaS saves operations work but gives you less control than IaaS.

Examples

1. As a two-person team, we picked a PaaS so we wouldn't have to manage servers at all.

2. The PaaS handles scaling, but it doesn't let us install custom system packages.

Common phrases

PaaS provider · PaaS platform · deploy to a PaaS · PaaS offering

SaaS

abbreviation

Meaning

Short for software as a service: complete software that customers use through a browser or app and pay for by subscription, while the vendor runs everything behind it.

Where you use it

Pronounced 'sass'. Email services, CRM systems and team chat tools are typical SaaS products. It is also used as an adjective for companies: 'a SaaS startup', 'SaaS business model'.

Examples

1. We replaced our self-hosted ticket system with a SaaS tool, so there's one less server to maintain.

2. Most SaaS companies charge per user per month.

Common phrases

SaaS product · SaaS company · SaaS subscription · SaaS platform

serverless

adjective

Meaning

Describes a way of running code in which the provider starts and scales servers automatically for each request, and you pay only for the time your code actually runs.

Where you use it

Used as an adjective ('serverless function', 'serverless architecture') and as a noun ('we use serverless'). AWS Lambda and Azure Functions are well-known examples. A 'cold start' is the short delay when a function starts after being idle.

Examples

1. The image resizing runs as a serverless function, so it costs almost nothing when nobody uploads.

2. Serverless is great for spiky traffic, but cold starts can hurt latency.

Usage note

Servers still exist; 'serverless' only means you don't manage them yourself.

Common phrases

serverless function · serverless architecture · go serverless · cold start

on-premises

adjective

Meaning

Describes servers and software that a company runs in its own building or data center, rather than renting them from a cloud provider.

Where you use it

Often shortened to 'on-prem' in speech. Used before nouns ('on-premises servers') and after verbs ('run on-premises'). Banks and public institutions often keep some systems on-premises for regulatory reasons.

Examples

1. Our customer data stays on-premises, but the website runs in the cloud.

2. Moving from on-premises hardware to the cloud took us almost two years.

Usage note

Many people say 'on-premise', but a premise is an idea; premises (with -s) means a building. 'On-premises' or 'on-prem' is the correct form.

Common phrases

on-premises servers · run on-premises · on-premises data center · on-premises to cloud migration

hybrid cloud

noun

Meaning

A setup that combines a company's own on-premises systems or private cloud with a public cloud provider, with the two connected and working together.

Where you use it

Common in banks, telecoms and large enterprises that cannot move everything to the cloud. Compare 'public cloud' (shared provider), 'private cloud' (for one organization) and 'multi-cloud' (several public providers).

Examples

1. We use a hybrid cloud: core banking stays in our data center, and the mobile backend runs on a public cloud.

2. A hybrid cloud needs a secure, fast connection between the two sides.

Usage note

Hybrid cloud mixes your own infrastructure with a public cloud; multi-cloud means using more than one public cloud provider.

Common phrases

hybrid cloud strategy · hybrid cloud environment · public cloud · private cloud · multi-cloud

availability zone

noun

Meaning

One of several separate data center locations inside a cloud region, each with its own power and network, so a failure in one should not affect the others.

Where you use it

Usually shortened to AZ. Engineers spread servers 'across multiple AZs' to survive a data center failure. AWS and Azure use 'availability zone'; Google Cloud simply says 'zone'.

Examples

1. The database has a standby copy in another availability zone, so it survived the power failure.

2. All our nodes were in a single availability zone, which was a big mistake.

Common phrases

across availability zones · multi-AZ · single availability zone · zone failure

container image

noun

Meaning

A read-only package with an application, its libraries and settings, used as the template from which containers are started.

Where you use it

You build an image, tag it with a version, push it to a registry and pull it on servers. People often just say 'image' or 'Docker image'. Small images download and start faster.

Examples

1. The new container image is 300 MB smaller because we switched to a slim base image.

2. Always tag the container image with the commit hash, not just 'latest'.

Common phrases

build an image · push an image · pull an image · base image · image tag

cluster

noun

Meaning

A group of connected machines that work together as one system, for example to run containers in Kubernetes or to store data in a database.

Where you use it

Most often heard as 'Kubernetes cluster', but also 'database cluster' and 'Elasticsearch cluster'. You create, upgrade, scale and delete clusters. Teams often keep separate clusters for staging and production.

Examples

1. We're upgrading the production cluster this weekend, so expect a few pod restarts.

2. The cluster has six nodes spread across three availability zones.

Common phrases

Kubernetes cluster · create a cluster · upgrade the cluster · cluster autoscaler · database cluster

node

noun

Meaning

One machine, physical or virtual, that is part of a cluster. In Kubernetes, worker nodes are the machines where pods actually run.

Where you use it

Nodes are added, drained (emptied of pods before maintenance), cordoned and removed. A 'node pool' or 'node group' is a set of nodes with the same machine type. Do not confuse it with Node.js.

Examples

1. One node ran out of memory, and Kubernetes moved its pods to the others.

2. Drain the node before you patch it, otherwise users will see errors.

Common phrases

worker node · node pool · drain a node · add a node · node failure

pod

noun

Meaning

The smallest unit that Kubernetes runs: one or more containers that are always placed together on the same node and share a network address and storage.

Where you use it

Pods are created, scheduled, restarted, evicted and killed. Engineers check pod status with kubectl: Running, Pending or CrashLoopBackOff. Pods are temporary; a Deployment replaces them when they die.

Examples

1. The pod is stuck in CrashLoopBackOff, so let's look at its logs.

2. Each pod runs the app container plus a small sidecar that ships logs.

Common phrases

pod status · restart a pod · pod crashed · pending pod · kill a pod

orchestration

noun

Meaning

The automatic management of many containers or services: deciding where they run, starting and restarting them, connecting them and scaling them.

Where you use it

Usually in the phrase 'container orchestration'. Kubernetes is the dominant orchestration tool; others include Docker Swarm, HashiCorp Nomad and Amazon ECS. The tool itself is called an orchestrator.

Examples

1. Once we had forty containers, we needed proper orchestration instead of shell scripts.

2. Container orchestration takes care of restarts, so you don't have to watch every service.

Usage note

Stress is on 'stra': or-ke-STRAY-shun. The 'ch' is pronounced like 'k'.

Common phrases

container orchestration · orchestration platform · orchestration tool · orchestration layer

continuous integration

noun

Meaning

The practice of merging small code changes into the shared main branch often, with each change automatically built and tested so problems are found early.

Where you use it

Shortened to CI. 'CI' also names the system that runs the checks: 'CI is failing', 'wait for CI to pass'. Tools include GitHub Actions, GitLab CI, Jenkins and CircleCI.

Examples

1. Continuous integration catches most broken merges within ten minutes.

2. Our continuous integration setup runs unit tests and a security scan on every pull request.

Common phrases

continuous integration server · CI pipeline · CI is green · wait for CI

continuous delivery

noun

Meaning

The practice of keeping code always ready to release, so that any tested version can go to production at the push of a button.

Where you use it

Shortened to CD, together with CI in 'CI/CD'. In continuous delivery a person still approves the final production step; in continuous deployment that step is automatic too.

Examples

1. With continuous delivery, releasing is a business decision, not a technical project.

2. We practise continuous delivery, but a product manager approves each production release.

Usage note

Continuous delivery and continuous deployment are both shortened to CD but are not the same; check which one people mean.

Common phrases

practise continuous delivery · continuous delivery pipeline · continuous deployment

artifact

noun

Meaning

A file or package produced by a build, such as a JAR file, a binary or a container image, which is stored and later deployed.

Where you use it

Pipelines produce, upload, store and promote artifacts. A common rule is 'build once, deploy many': the same artifact goes to staging and then to production. Artifacts are kept in tools such as Artifactory or Nexus.

Examples

1. The pipeline uploads the artifact to the repository, and the deploy job picks it up from there.

2. We deploy exactly the same artifact that passed the tests on staging.

Usage note

British English writes 'artefact' in general texts, but software tools almost always use the American spelling 'artifact'.

Common phrases

build artifact · artifact repository · upload an artifact · promote an artifact

load balancer

noun

Meaning

A service that receives incoming traffic and spreads it across several servers, sending requests only to the ones that are healthy.

Where you use it

Sits in front of web servers or pods. Engineers put servers 'behind a load balancer' and configure health checks and listeners. Examples are AWS Application Load Balancer, Nginx and HAProxy. Often shortened to LB.

Examples

1. The load balancer took the broken server out of rotation after three failed health checks.

2. We put two more instances behind the load balancer before the sale started.

Common phrases

behind a load balancer · application load balancer · load balancer health check · configure a load balancer

autoscaling

noun

Meaning

Automatically adding servers or containers when demand rises and removing them when it falls, based on rules such as CPU use or number of requests.

Where you use it

Also written 'auto scaling' or 'auto-scaling'. Examples are AWS Auto Scaling groups and the Kubernetes Horizontal Pod Autoscaler. Teams set minimum and maximum limits and a target, such as 60 percent CPU.

Examples

1. Autoscaling added twelve pods during the match, then removed them when traffic dropped.

2. Set a maximum for autoscaling, or a traffic spike could double the bill.

Common phrases

autoscaling group · autoscaling policy · enable autoscaling · autoscaling rules

latency

noun

Meaning

The time a request or piece of data takes to travel through a system and get a response, usually measured in milliseconds.

Where you use it

Latency is high or low, spikes and increases. Teams track percentiles such as p95 or p99 latency (the time within which 95 or 99 percent of requests finish), because averages hide slow requests.

Examples

1. p99 latency went from 200 to 900 milliseconds after the new release.

2. Users in Asia see higher latency because all our servers are in Europe.

Common phrases

high latency · low latency · latency spike · p99 latency · reduce latency

provision

verb

Meaning

To create and set up computing resources, such as servers, databases or networks, so they are ready to use.

Where you use it

Very common in cloud work: 'provision a database', 'provision infrastructure with Terraform'. The noun is 'provisioning'. 'Overprovisioned' means you have more capacity than you need, which wastes money.

Examples

1. The pipeline provisions a fresh database for every test run.

2. It used to take two weeks to provision a server; now it takes two minutes.

Usage note

In general English 'provisions' (plural noun) can mean food supplies or legal clauses; in the cloud the verb means creating resources.

Common phrases

provision infrastructure · provision a server · automated provisioning · overprovisioned

Terraform

noun

Meaning

A widely used infrastructure-as-code tool from HashiCorp. You describe resources in configuration files, and it creates, changes or deletes them to match.

Where you use it

Files are written in HCL (HashiCorp Configuration Language). The main commands are 'terraform plan' (show what will change) and 'terraform apply' (make the changes). It keeps track of resources in a state file. OpenTofu is an open-source fork.

Examples

1. Always read the Terraform plan before you apply it; one wrong line can delete a database.

2. All our AWS accounts are managed with Terraform, so nothing is created by hand.

Common phrases

Terraform plan · Terraform apply · Terraform module · Terraform state · Terraform provider

configuration management

noun

Meaning

Using tools to keep the software, settings and files on many servers in a known, consistent state, instead of changing each server by hand.

Where you use it

Ansible, Puppet, Chef and Salt are the classic tools. Terraform usually creates the servers, and a configuration management tool sets up what runs on them. Ansible files are called playbooks.

Examples

1. With configuration management, patching 200 servers is one command instead of a week of work.

2. We use Ansible for configuration management and Terraform for the cloud resources.

Common phrases

configuration management tool · Ansible playbook · configuration drift · manage configuration

spin up

phrasal verb

Meaning

To quickly create and start a new server, container or environment, usually with a command or a few clicks.

Where you use it

Informal but used everywhere in the industry: 'spin up an instance', 'spin up a test environment'. The past form is 'spun up'. The opposite is 'spin down' or 'tear down'.

Examples

1. Can you spin up a copy of staging so I can test the migration?

2. The CI job spins up a database container, runs the tests and then removes it.

Common phrases

spin up an instance · spin up a cluster · spin up a test environment · spin up containers

hypervisor

noun

Meaning

Software that creates and runs virtual machines, sharing one physical computer's CPU, memory and storage between them and keeping them separate.

Where you use it

Type 1 hypervisors run directly on the hardware (VMware ESXi, Microsoft Hyper-V, KVM, Xen); type 2 hypervisors run on top of a normal operating system (VirtualBox). Cloud users rarely touch the hypervisor directly.

Examples

1. Our on-premises hypervisor hosts about forty virtual machines on four physical servers.

2. The cloud provider patched the hypervisor, and some instances had to be restarted.

Common phrases

type 1 hypervisor · bare-metal hypervisor · hypervisor host · hypervisor layer

workload

noun

Meaning

An application, service or job that runs on cloud resources and uses computing power, for example a website, a batch job or a database.

Where you use it

A general word in cloud planning and documentation: 'migrate workloads to the cloud', 'production workloads', 'stateless workloads'. In Kubernetes, Deployments and Jobs are called workload resources.

Examples

1. We moved the batch workloads to spot instances, which cut their cost by more than half.

2. Not every workload belongs in the cloud; some legacy systems are cheaper to run on-premises.

Usage note

In everyday English 'workload' means the amount of work a person has. In the cloud it means a running application or job.

Common phrases

production workload · migrate workloads · run a workload · stateless workload

managed service

noun

Meaning

A cloud service where the provider handles setup, patching, backups and scaling, so you only use it and do not manage the servers underneath.

Where you use it

Common examples are managed databases (Amazon RDS, Azure SQL Database, Cloud SQL), managed Kubernetes and managed queues. Teams choose a managed service to reduce operations work, at a higher price per unit.

Examples

1. We switched to a managed service for PostgreSQL, so backups and failover are no longer our problem.

2. A managed service costs more per hour, but it saves us a full-time engineer.

Common phrases

fully managed service · managed database · managed Kubernetes · use a managed service

object storage

noun

Meaning

A type of cloud storage that keeps files as objects, each with a unique key and metadata, and lets you read and write them over an HTTP API.

Where you use it

Used for images, videos, backups, logs and data lakes. Amazon S3 is the best-known example; Azure Blob Storage and Google Cloud Storage are similar. Compare it with block storage (disks for VMs) and file storage (shared folders).

Examples

1. User uploads go straight to object storage, not to the application servers.

2. Object storage is cheap for large files, but it isn't a replacement for a database.

Common phrases

object storage service · S3-compatible object storage · store files in object storage · block storage

bucket

noun

Meaning

A named container in object storage, such as Amazon S3 or Google Cloud Storage, that holds files and has its own access and storage settings.

Where you use it

You create a bucket, upload objects to it and set a bucket policy. Bucket names in S3 must be unique across all customers. A 'public bucket' that should be private is a common cause of data leaks.

Examples

1. The logs are archived to an S3 bucket and deleted after ninety days.

2. Someone made the bucket public by mistake, so we blocked public access and checked the access logs.

Usage note

Azure Blob Storage calls the same idea a 'container', which can be confusing next to Docker containers.

Common phrases

S3 bucket · create a bucket · bucket policy · public bucket · storage bucket

VPC

abbreviation

Meaning

Short for virtual private cloud: your own isolated private network inside a public cloud, where you control IP ranges, subnets, routing and access.

Where you use it

Said letter by letter, 'V-P-C'. AWS and Google Cloud use this name; Azure calls it a virtual network (VNet). Teams create VPCs, split them into subnets and connect them with peering or VPN.

Examples

1. The database sits in a private part of the VPC and can't be reached from the internet.

2. We need VPC peering so the analytics account can read from the production database.

Common phrases

create a VPC · VPC peering · inside the VPC · default VPC

subnet

noun

Meaning

A smaller range of IP addresses inside a larger network such as a VPC, used to group resources and control which of them can reach the internet.

Where you use it

Teams talk about public subnets (with a route to the internet, for load balancers) and private subnets (no direct internet access, for databases). Subnets are written in CIDR notation, such as 10.0.1.0/24.

Examples

1. Put the application servers in the private subnet and only the load balancer in the public one.

2. We ran out of IP addresses because the subnet was only a /26.

Common phrases

public subnet · private subnet · subnet mask · CIDR range

pay-as-you-go

adjective

Meaning

Describes a pricing model in which you pay only for the resources you actually use, for example by the second, hour or gigabyte, with no long-term contract.

Where you use it

The default pricing in the cloud, also called on-demand pricing. Used before nouns ('pay-as-you-go pricing', 'a pay-as-you-go plan'). It is flexible but more expensive per hour than reserved capacity.

Examples

1. Pay-as-you-go pricing is perfect for our test environments, which only run during office hours.

2. We started on a pay-as-you-go plan and moved to reserved instances once usage was stable.

Common phrases

pay-as-you-go pricing · pay-as-you-go model · on-demand pricing · pay-as-you-go plan

cost optimization

noun

Meaning

Reducing cloud spending without hurting performance or reliability, for example by removing unused resources, choosing the right sizes and using discounts.

Where you use it

A regular topic for DevOps teams and finance. Common actions are rightsizing (making instances smaller), deleting idle resources, tagging costs by team and buying reserved capacity. The practice is often called FinOps.

Examples

1. Our cost optimization work this quarter saved about 20 percent, mostly by deleting idle test servers.

2. Cost optimization starts with tagging, because you can't fix costs you can't see.

Usage note

British English spells it 'optimisation'; cloud provider documents use the American 'optimization'.

Common phrases

cloud cost optimization · cost optimization review · rightsizing · reduce cloud spend

snapshot

noun

Meaning

A copy of a disk, volume or database exactly as it was at one moment in time, which can be used to restore it or create a new copy.

Where you use it

Snapshots are taken before risky changes and on a schedule. Cloud disk snapshots are usually incremental, storing only blocks that changed. People often say 'take a snapshot before the upgrade'.

Examples

1. Take a snapshot of the volume before you resize it, just in case.

2. We restored the database from last night's snapshot and lost only two hours of data.

Usage note

Some snapshots depend on the original disk, so a snapshot is not always a full, independent backup.

Common phrases

take a snapshot · restore from a snapshot · disk snapshot · automated snapshots

scale out

phrasal verb

Meaning

To handle more load by adding more servers, containers or instances that share the work, rather than making one machine bigger.

Where you use it

Also called horizontal scaling. The opposite, removing servers when load drops, is 'scale in'. Stateless services scale out easily; databases are harder. Autoscaling usually scales out and in automatically.

Examples

1. During the campaign we scaled out from four to twenty web servers.

2. The service keeps sessions in memory, so we can't scale out until we move them to Redis.

Common phrases

scale out horizontally · scale out and in · horizontal scaling · scale out the web tier

scale up

phrasal verb

Meaning

To handle more load by giving one machine more power, such as more CPU or memory, instead of adding more machines.

Where you use it

Also called vertical scaling. The opposite is 'scale down'. It is simple but has a limit (the biggest machine available) and often needs a restart. Databases are frequently scaled up before they are split.

Examples

1. We scaled up the database to 32 CPUs, which bought us six more months.

2. Scaling up is quick, but it doesn't help if the server itself goes down.

Usage note

In general business English 'scale up' just means 'grow'. In infrastructure it specifically means making one machine bigger.

Common phrases

scale up vertically · scale up the database · vertical scaling · scale down

throughput

noun

Meaning

The amount of work a system completes in a given time, for example requests per second, messages per minute or megabytes per second.

Where you use it

Usually discussed together with latency: latency is how long one request takes, throughput is how many requests finish per second. Requests per second is often written RPS. Throughput increases, drops or hits a ceiling.

Examples

1. After the fix, throughput went up from 2,000 to 5,000 requests per second.

2. The disk throughput is the limit here, not the CPU.

Usage note

The 'ough' is pronounced like 'oo' in 'too': THROO-put.

Common phrases

high throughput · increase throughput · requests per second · network throughput

bottleneck

noun

Meaning

The one slowest or most limited part of a system, such as the database or the network, that holds back the performance of everything else.

Where you use it

Teams 'find', 'hit' and 'remove' bottlenecks. Fixing one bottleneck often reveals the next one. Load tests and tracing are common ways to find them. The word is also used for people and processes.

Examples

1. Adding more web servers didn't help, because the database was the real bottleneck.

2. The load test showed a bottleneck in the image service at 800 requests per second.

Common phrases

performance bottleneck · find the bottleneck · remove a bottleneck · become a bottleneck

blue-green deployment

noun

Meaning

A release method with two identical production environments: the new version is put on the idle one, then all traffic is switched to it at once.

Where you use it

Blue is usually the current version and green the new one. If something goes wrong, rollback is just switching traffic back. The trade-off is paying for two full environments during the switch.

Examples

1. With blue-green deployment, our rollback takes seconds instead of half an hour.

2. The database schema must work with both versions during a blue-green deployment.

Common phrases

blue-green deployment strategy · switch traffic · blue-green release · zero-downtime deployment

canary release

noun

Meaning

Releasing a new version to a small share of users or servers first, watching its metrics, and only then rolling it out to everyone.

Where you use it

Also called a canary deployment; the first small group is 'the canary'. Traffic might go 1 percent, then 10, then 50, then 100. If errors rise, the canary is rolled back before most users are affected.

Examples

1. The canary release went to 5 percent of users, and error rates stayed flat, so we continued.

2. Our pipeline stops the canary release automatically if p99 latency goes up by more than 20 percent.

Usage note

The name comes from miners who took canaries into coal mines: if the bird got sick, it warned them of dangerous gas.

Common phrases

canary release · canary deployment · promote the canary · canary analysis

feature flag

noun

Meaning

A setting that turns a feature on or off without deploying new code, so it can be shown to some users, tested in production or switched off quickly.

Where you use it

Also called a feature toggle. Code is shipped 'behind a feature flag' and the flag is later 'turned on' or 'flipped'. Old flags that nobody removes become technical debt. LaunchDarkly and Unleash are common tools.

Examples

1. The new checkout is already in production behind a feature flag; we'll turn it on for staff first.

2. When errors started, we just switched off the feature flag instead of doing a rollback.

Common phrases

behind a feature flag · turn on a feature flag · flip a flag · feature toggle

roll out

phrasal verb

Meaning

To release a new version, feature or change to users or servers, often step by step over a period of time rather than all at once.

Where you use it

Very common in release talk: 'roll out to 10 percent of users', 'roll out gradually'. The noun is one word, 'rollout': 'a staged rollout'. In Kubernetes, 'kubectl rollout' commands manage updates.

Examples

1. We'll roll out the new search to Turkey first and then to the other markets.

2. The security patch was rolled out to all nodes overnight.

Usage note

Do not mix up 'roll out' (release forward) with 'roll back' (go back to the old version).

Common phrases

roll out gradually · staged rollout · roll out a feature · roll out a patch

Dockerfile

noun

Meaning

A text file with step-by-step instructions, such as FROM, COPY and RUN, that Docker follows to build a container image.

Where you use it

Usually named exactly 'Dockerfile', with a capital D and no extension, in the project's root folder. Engineers write, review and optimize Dockerfiles; multi-stage builds keep final images small.

Examples

1. Add the new dependency to the Dockerfile, or the image won't build in CI.

2. I rewrote the Dockerfile as a multi-stage build, and the image went from 1 GB to 150 MB.

Common phrases

write a Dockerfile · multi-stage Dockerfile · Dockerfile instruction · base image

container registry

noun

Meaning

A storage service for container images, where pipelines push new images and servers or clusters pull them when they need to run them.

Where you use it

Often just 'the registry'. Examples are Docker Hub, Amazon ECR, Azure Container Registry, Google Artifact Registry and GitHub Container Registry. Many registries scan images for known vulnerabilities.

Examples

1. The pods can't start because the cluster has no permission to pull from the container registry.

2. Our private container registry deletes untagged images after two weeks.

Common phrases

push to the registry · pull from the registry · private container registry · image scanning

YAML

noun

Meaning

A human-readable text format for configuration files that uses indentation and simple 'key: value' lines. Most DevOps tools are configured with it.

Where you use it

Pronounced 'YAM-ul'. Used for Kubernetes manifests, GitHub Actions and GitLab CI pipelines, Ansible playbooks and Docker Compose files. Indentation must use spaces, never tabs, and one wrong space can break a file.

Examples

1. The pipeline failed because of a single wrong indent in the YAML file.

2. Run a linter on your YAML before you push it.

Usage note

Files may end in .yaml or .yml; both are correct. The name now officially stands for 'YAML Ain't Markup Language'.

Common phrases

YAML file · YAML manifest · YAML syntax · edit the YAML

reserved instance

noun

Meaning

Cloud capacity you commit to use for one or three years in exchange for a large discount compared with normal on-demand prices.

Where you use it

Shortened to RI. The term comes from AWS; Azure has reserved VM instances and Google Cloud has committed use discounts. AWS Savings Plans work in a similar way. Best for steady, predictable workloads.

Examples

1. Our databases run all year, so we bought reserved instances for them.

2. Before you buy a reserved instance, make sure the workload won't shrink next year.

Common phrases

buy reserved instances · reserved instance coverage · savings plan · committed use discount

spot instance

noun

Meaning

Spare cloud capacity sold at a much lower price, which the provider can take back at short notice when it needs the capacity again.

Where you use it

On AWS, a spot instance gets about a two-minute warning before it is interrupted. Azure and Google Cloud call them Spot VMs. Good for batch jobs, CI runners and stateless workers that can restart safely.

Examples

1. Our CI runners use spot instances, which cut the bill by about 70 percent.

2. Don't run the database on a spot instance; it can disappear at any time.

Common phrases

spot instance interruption · spot pricing · run on spot · spot VM

egress

noun

Meaning

Data leaving a network, for example from a cloud provider to the internet or to another region. Cloud providers usually charge for egress but not for incoming data.

Where you use it

Common in cost and network talk: 'egress fees', 'egress costs', 'egress traffic'. The opposite is ingress (incoming traffic). In Kubernetes, 'Ingress' is also the name of an object that routes incoming HTTP traffic.

Examples

1. Egress was a third of our cloud bill because users downloaded videos straight from storage.

2. Putting a CDN in front of the bucket reduced our egress costs a lot.

Common phrases

egress fees · egress traffic · data egress · ingress and egress

tear down

phrasal verb

Meaning

To delete a server, environment or set of resources completely when it is no longer needed, usually with a command or script.

Where you use it

The opposite of 'spin up'. The past form is 'tore down', the past participle 'torn down', and the noun is 'teardown'. With Terraform, 'terraform destroy' tears down everything in a configuration.

Examples

1. The pipeline tears down the preview environment as soon as the pull request is merged.

2. Remember to tear down the load test cluster tonight, or it will keep costing us money.

Usage note

'Tear' here rhymes with 'air' (to pull apart), not with 'ear' (a drop from your eye).

Common phrases

tear down an environment · tear down a cluster · spin up and tear down · teardown script

beta testing

noun

Meaning

Testing a nearly finished version of an app with a group of real users before the public release, to find bugs and collect feedback.

Where you use it

iOS teams run beta testing through TestFlight, and Android teams use Google Play's internal, closed and open testing tracks or tools such as Firebase App Distribution. People join a beta, become beta testers and send beta feedback.

Examples

1. Beta testing with 200 users found three crashes we never saw in the office.

2. Open beta testing starts on Monday for Android users.

Common phrases

join the beta · beta tester · open beta · closed beta · beta feedback

app icon

noun

Meaning

The small image that represents an app on the home screen, in the store and in the settings; it is often the first thing users notice.

Where you use it

Designers deliver the app icon in several sizes, including 1024 × 1024 pixels for the App Store and 512 × 512 for Google Play. Android uses adaptive icons that can be shown in different shapes, and some apps offer alternate icons that users can choose.

Examples

1. The new app icon looks blurry on some Android launchers.

2. We're testing two app icons to see which one gets more downloads.

Common phrases

app icon design · adaptive icon · alternate app icon · app icon size

reject

verb

Meaning

To refuse to accept an app or update into the store because it breaks a store rule or does not work properly during review.

Where you use it

Usually passive: the app was rejected, the build got rejected. Apple gives the reason with a guideline number; common causes are a crash during review, no way to delete an account, or unclear permission texts. Developers fix the issue and resubmit, or reply and appeal.

Examples

1. Apple rejected our update because the reviewer couldn't log in with the demo account.

2. If the build is rejected again, we'll miss the campaign date.

Common phrases

get rejected · rejected by Apple · rejection reason · resubmit after rejection

TestFlight

noun

Meaning

Apple's service for sending beta builds of iOS apps to testers, who install them with the TestFlight app before the version is released on the App Store.

Where you use it

Teams upload a build to TestFlight, add internal testers from their team and invite external testers by email or a public link. Builds for external testers go through a short beta review, and each build expires after 90 days.

Examples

1. The new build is on TestFlight; please check the payment flow today.

2. We invited the client to TestFlight so they can try the app before launch.

Common phrases

upload to TestFlight · TestFlight build · TestFlight invite · external testers · public link

store listing

noun

Meaning

The page for an app in an app store, with its name, icon, description, screenshots, ratings and other information that helps users decide to download it.

Where you use it

'Store listing' is Google Play's term; Apple calls it the product page. Teams update the listing text, screenshots and preview videos, translate the listing for different countries and test different versions of it to get more installs.

Examples

1. Marketing rewrote the store listing and added Turkish screenshots.

2. The store listing still mentions a feature we removed last year.

Common phrases

update the store listing · store listing experiment · localized store listing · product page

version number

noun

Meaning

The number that identifies a release of an app for users, such as 3.2.1, shown in the store and usually in the app's settings.

Where you use it

Each platform also has a separate build number: on iOS, version (CFBundleShortVersionString) and build (CFBundleVersion); on Android, versionName and versionCode, a whole number that must increase with each upload. Many teams use semantic versioning: major.minor.patch.

Examples

1. Please include the version number and your phone model in every bug report.

2. We bumped the version number to 4.0 because of the redesign.

Common phrases

bump the version number · version and build number · minimum version · semantic versioning

code signing

noun

Meaning

Adding a digital signature to an app with a certificate, which proves who made it and shows that it has not been changed since it was built.

Where you use it

Required on both platforms. On iOS it involves certificates, provisioning profiles and Xcode's signing settings, and it is a well-known source of build errors. On Android, apps are signed with a key from a keystore; with Play App Signing, Google keeps the final app signing key.

Examples

1. The CI build fails at the code signing step because the certificate has expired.

2. Automatic code signing in Xcode solved most of our profile problems.

Common phrases

code signing certificate · code signing error · automatic signing · app signing key

provisioning profile

noun

Meaning

An Apple file that connects an app ID, signing certificates and, for testing, specific devices, so that a signed iOS app is allowed to run or be distributed.

Where you use it

There are development, ad hoc, App Store and enterprise profiles. Developers create, download and renew them in the Apple Developer portal, or let Xcode manage them automatically. Errors such as 'no matching provisioning profile' are a common topic in team chats.

Examples

1. Add the tester's iPhone to the provisioning profile, or the ad hoc build won't install.

2. The provisioning profile expired, so the company's internal app stopped opening.

Common phrases

renew a provisioning profile · ad hoc provisioning profile · development profile · no matching provisioning profile

bundle ID

noun

Meaning

A unique identifier for an app, usually written in reverse domain style such as com.company.appname, which the system and the store use to recognize it.

Where you use it

The iOS term; Android calls it the application ID or package name. It is set at the start of a project and cannot be changed once the app is published, so teams choose it carefully. Test and production versions often use separate IDs.

Examples

1. Use a different bundle ID for the staging app so testers can install both versions.

2. The push certificate was created for the wrong bundle ID.

Common phrases

bundle ID · package name · application ID · register a bundle ID

staged rollout

noun

Meaning

Releasing an update to a small percentage of users first and increasing it step by step, so problems can be found before everyone gets the new version.

Where you use it

Google Play's term: you start a staged rollout at, for example, 5%, then increase, halt or complete it. Apple offers a similar 'phased release' that spreads automatic updates over seven days. Teams watch crash rates closely during a rollout.

Examples

1. We paused the staged rollout at 10% because crashes doubled on Android 13.

2. If the numbers look good tomorrow, increase the staged rollout to 50%.

Common phrases

start a staged rollout · halt the rollout · increase the rollout · phased release

force update

noun

Meaning

A screen or rule that blocks an old version of an app and makes users install the latest one before they can continue using it.

Where you use it

Also called a forced or mandatory update. Teams set a minimum supported version on the server and use it when an old version has a serious bug or no longer works with the API. On Android, Google Play's In-App Updates API offers an 'immediate' update flow for this.

Examples

1. Version 2.3 has a payment bug, so we're adding a force update for everyone below 2.4.

2. Users hate seeing a force update screen when they're in a hurry.

Common phrases

force update · minimum supported version · mandatory update · force users to update

ASO

abbreviation

Meaning

App Store Optimization: improving an app's store page, such as its title, keywords, screenshots and ratings, so it ranks higher in search and gets more downloads.

Where you use it

Often described as 'SEO for apps', and it applies to both the App Store and Google Play. ASO specialists work on keywords, localized listings and A/B tests of icons and screenshots, and follow keyword rankings and conversion rates.

Examples

1. After the ASO work, we rank in the top five for 'budget planner' in Turkey.

2. Our ASO agency suggested changing the subtitle and the first two screenshots.

Common phrases

ASO strategy · ASO keywords · improve ASO · ASO specialist

DLC

abbreviation

Meaning

Short for downloadable content: extra content released for a game after it comes out, such as new levels, characters, story chapters or costumes, often sold separately.

Where you use it

Said letter by letter: D-L-C. Large DLCs are called expansions. Publishers plan DLC in a season pass or roadmap, and players complain when content seems cut from the main game to be sold as day-one DLC.

Examples

1. The first DLC adds a new region and about ten hours of story.

2. We're keeping two artists on the team after launch to work on DLC.

Common phrases

release DLC · paid DLC · free DLC · DLC pack · season pass

platform

noun

Meaning

The hardware or store that a game runs on and is sold through, such as PC, PlayStation, Xbox, Nintendo Switch, iOS or Android, or a store like Steam.

Where you use it

The companies that own consoles are called platform holders. Games can be platform exclusives or multi-platform; cross-platform play lets people on different devices play together. Each platform has its own technical rules.

Examples

1. We're launching on PC first and bringing the game to other platforms next year.

2. Cross-platform play was the most requested feature on our forums.

Usage note

In gameplay, a platform is also a surface the character jumps on, which is where the genre name 'platformer' comes from.

Common phrases

platform holder · cross-platform play · platform exclusive · target platform · multi-platform release

localization

noun

Meaning

Adapting a game for players who speak another language and live in another culture: translating text and voice, and adjusting things like fonts, dates, jokes and images.

Where you use it

Often shortened to loc or L10n. Localization teams and vendors work from string tables, and localization QA (LQA) checks the text inside the game. A common problem is German or Turkish UI text being longer than the English and not fitting.

Examples

1. The Turkish localization made several menu labels too long, so we had to resize the buttons.

2. Don't hard-code strings; all text must go through the localization system.

Usage note

Turkish has special letters like ı, İ, ş and ğ. Check that the game's fonts support them and that the code converts I and i correctly when it changes letter case.

Common phrases

localization team · localization QA · localization vendor · string table · localization-ready

live service

noun

Meaning

A model in which a game is updated continuously for years after launch with new content, events and seasons, to keep players playing and spending.

Where you use it

Also called games as a service (GaaS). The day-to-day work of running it is called live ops: events, offers, balance changes and community management. Many live-service games are free-to-play with a battle pass.

Examples

1. A live service game needs a team ready to ship new content every few weeks.

2. The live service roadmap has a seasonal event every month for the first year.

Common phrases

live-service game · live ops · games as a service · seasonal content · content roadmap

DAU

abbreviation

Meaning

Short for daily active users: the number of different people who play a game on a given day. MAU is the same figure for a month.

Where you use it

Used in dashboards, investor updates and live-ops meetings. The DAU/MAU ratio shows how often monthly players return, a sign of how 'sticky' a game is. Revenue metrics such as ARPDAU, average revenue per daily active user, are based on it.

Examples

1. DAU jumped to 80,000 during the Halloween event.

2. Our DAU is stable, but fewer players are making purchases.

Common phrases

DAU/MAU ratio · grow DAU · peak DAU · MAU

SQL

abbreviation

Meaning

Structured Query Language: the standard language used to create tables and to read, add, change and delete data in relational databases.

Where you use it

Used in job ads ('strong SQL skills'), interviews and daily work. People write SQL, run SQL, and talk about 'raw SQL' when they skip an ORM. Each product adds its own dialect, such as T-SQL (SQL Server) or PL/SQL (Oracle), on top of the standard.

Examples

1. You don't need Python for this report; a few lines of SQL will do.

2. Candidates take a one-hour SQL test before the technical interview.

Usage note

Both 'S-Q-L' and 'sequel' are correct. The article follows the sound: 'an S-Q-L query' but 'a sequel query'.

Common phrases

write SQL · run a SQL query · raw SQL · SQL dialect · SQL skills

table

noun

Meaning

A structure in a relational database that stores data about one kind of thing in rows and columns, for example all customers or all orders.

Where you use it

The main building block of a relational database. You create, alter, drop, truncate, join and query tables. Teams agree on naming rules, such as plural or singular table names (customers or customer) and snake_case.

Examples

1. Order details are stored in a separate table called order_items.

2. Who dropped the test table? My scripts are failing now.

Common phrases

create a table · drop a table · join two tables · lookup table · table name

column

noun

Meaning

A vertical part of a table with a name and a data type, holding one kind of information for every row, such as email or created_at.

Where you use it

You add, rename, drop and index columns, and you choose which columns a query returns. Common phrases: 'nullable column', 'computed column', 'column name', 'SELECT only the columns you need'. Some tools and older texts call a column a field.

Examples

1. We need to add a phone_number column to the customers table.

2. Avoid SELECT * and list only the columns the screen actually uses.

Usage note

The final 'n' is silent: say 'KOL-um', not 'kol-umn'.

Common phrases

add a column · drop a column · column name · nullable column · rename a column

query

noun

Meaning

A request sent to a database to read or change data, usually written in SQL. As a verb, to query means to ask a database for data.

Where you use it

One of the most frequent words in the field. You write, run, execute, optimize and tune queries; a query returns rows, times out or takes too long. 'Query' is also a verb: 'query the orders table'. In everyday English, 'query' can simply mean a question from a customer.

Examples

1. This query takes eight seconds; can you check whether it uses an index?

2. The dashboard queries the database every thirty seconds.

Common phrases

run a query · write a query · slow query · query results · query the database

relational database

noun

Meaning

A type of database that stores data in tables made of rows and columns and links tables to each other through keys. Data is usually managed with SQL.

Where you use it

Based on the relational model that Edgar F. Codd described in 1970. PostgreSQL, MySQL, Oracle, SQL Server and SQLite are the best-known examples. The phrase is used mostly when comparing with NoSQL systems or in courses and architecture documents.

Examples

1. For payments we chose a relational database because we need strict consistency and transactions.

2. Most relational databases today also support JSON columns.

Common phrases

relational database management system · relational model · use a relational database · relational data

DBMS

abbreviation

Meaning

Database management system: the software that stores the data, runs queries, controls access and keeps data safe, such as PostgreSQL or Oracle.

Where you use it

Common in textbooks, university courses, job ads and vendor comparisons. RDBMS means a relational DBMS. In daily talk people usually name the product ('we're on Postgres') or say 'database engine' instead.

Examples

1. Which DBMS does the project use, MySQL or PostgreSQL?

2. The course covers how a DBMS handles storage, indexing and recovery.

Usage note

Say each letter: 'D-B-M-S'. The plural is DBMSs or DBMSes.

Common phrases

relational DBMS · choose a DBMS · DBMS vendor · open-source DBMS

primary key

noun

Meaning

A column, or a set of columns, whose value uniquely identifies each row in a table. It cannot be empty and no two rows can share it.

Where you use it

Every well-designed table has exactly one primary key, often an id column. People shorten it to PK in diagrams and chat. You define, add or change a primary key; a 'duplicate key' error means you tried to insert a value that already exists.

Examples

1. The primary key of the orders table is order_id.

2. The import failed with a primary key violation, so some IDs must already exist.

Common phrases

define a primary key · primary key column · primary key violation · composite primary key

foreign key

noun

Meaning

A column in one table that points to the primary key of another table, linking the two and stopping you from storing references to rows that do not exist.

Where you use it

Shortened to FK. You add or drop a foreign key, and a 'foreign key constraint fails' error means the referenced row is missing or still has child rows. Teams sometimes debate whether to enforce foreign keys in the database or only in application code.

Examples

1. orders.customer_id is a foreign key to customers.id.

2. I can't delete this customer because of a foreign key constraint on the invoices table.

Usage note

'Foreign' here has nothing to do with other countries; it means the key belongs to another table. The 'g' is silent: 'FOR-in'.

Common phrases

add a foreign key · foreign key constraint · foreign key reference · drop a foreign key

SELECT statement

noun

Meaning

The SQL statement that reads data from one or more tables and returns the matching rows without changing anything in the database.

Where you use it

The statement developers write most. Its main parts are SELECT, FROM, WHERE, GROUP BY, HAVING and ORDER BY. People say 'run a SELECT', 'a simple SELECT' or 'a read query'. 'SELECT *' returns all columns and is fine for exploring but discouraged in application code.

Examples

1. Before you run the DELETE, run the same WHERE condition in a SELECT statement to see which rows it hits.

2. The reporting user can only run SELECT statements; it has no write access.

Common phrases

run a SELECT statement · simple SELECT · SELECT * · SELECT query · nested SELECT

WHERE clause

noun

Meaning

The part of a SQL statement that sets a condition, so only the rows that meet it are read, updated or deleted.

Where you use it

Used in SELECT, UPDATE and DELETE. People talk about 'filtering in the WHERE clause' and warn each other about an UPDATE or DELETE 'without a WHERE clause', which changes every row. Conditions are combined with AND, OR, IN, BETWEEN and LIKE.

Examples

1. Someone ran an UPDATE without a WHERE clause and every price became zero.

2. Add status = 'active' to the WHERE clause so cancelled accounts are excluded.

Usage note

Turkish speakers often call every part of a query a 'condition'. In English, WHERE, FROM, GROUP BY and ORDER BY are each called a clause.

Common phrases

add to the WHERE clause · filter in the WHERE clause · without a WHERE clause · WHERE condition

join

noun

Meaning

A SQL operation that combines rows from two or more tables using a related column, such as a customer ID. As a verb, to join tables means to combine them this way.

Where you use it

Joins are at the heart of relational databases. The main types are inner join, left (outer) join, right join, full outer join and cross join. People 'join A to B' or 'join A with B on customer_id', and complain about queries with 'too many joins'.

Examples

1. Join the orders table to customers on customer_id to get the customer names.

2. The report is slow because of a join on a column without an index.

Common phrases

join two tables · join on a column · self-join · join condition · cross join

schema

noun

Meaning

The structure of a database: its tables, columns, data types, keys and relationships. In some products it is also a named group of tables inside a database.

Where you use it

Two meanings are common. 'Schema change' or 'schema design' refers to the structure. In PostgreSQL and SQL Server a schema is also a namespace like public or dbo, while in MySQL 'schema' and 'database' mean the same thing. You design, change, migrate and version a schema.

Examples

1. Any schema change on the production database must go through a migration script.

2. The new reporting tables live in a separate schema called analytics.

Usage note

Say 'SKEE-muh', not 'SHEE-ma'. The usual plural is 'schemas'; 'schemata' is rare and formal.

Common phrases

schema change · database schema · schema design · schema migration · schemaless

transaction

noun

Meaning

A group of database operations that are treated as one unit: either all of them succeed together or none of them is applied.

Where you use it

The classic example is a money transfer: the debit and the credit must both happen or neither. You begin or open a transaction, then commit or roll it back. Long-running or open transactions hold locks and cause trouble, so DBAs watch for them.

Examples

1. Wrap the stock update and the order insert in a single transaction.

2. A transaction has been open for two hours and is blocking the nightly job.

Usage note

In banking and business, 'transaction' means a payment or sale. In databases it is a technical unit of work, even when no money is involved.

Common phrases

begin a transaction · commit a transaction · roll back a transaction · open transaction · transaction log

data type

noun

Meaning

The kind of value a column can hold, such as whole numbers, text, dates or true/false values. It controls what can be stored and how much space it takes.

Where you use it

Chosen when you create or alter a column: INT, BIGINT, VARCHAR(255), TEXT, DATE, TIMESTAMP, BOOLEAN, DECIMAL(10,2). A wrong data type causes bugs and slow queries, for example storing dates as text or money as FLOAT. Names differ slightly between products.

Examples

1. Use DECIMAL, not FLOAT, as the data type for prices.

2. Changing the data type of a column on a table this big will lock it for a while.

Common phrases

choose a data type · change the data type · data type mismatch · numeric data type

NULL

noun

Meaning

A special marker meaning that a value is missing or unknown. It is not the same as zero or an empty string.

Where you use it

Columns are 'nullable' or 'NOT NULL'. Because NULL means unknown, 'x = NULL' is never true; you must write 'IS NULL' or 'IS NOT NULL'. NULLs also affect results: COUNT(column) and AVG skip them, and functions like COALESCE replace them with a default.

Examples

1. The query returned nothing because it used = NULL instead of IS NULL.

2. Half of the customers have NULL in the phone column.

Usage note

In Oracle an empty string is treated as NULL, while PostgreSQL, MySQL and SQL Server treat them as different values.

Common phrases

IS NULL · NOT NULL · nullable column · NULL value · allow NULLs

INSERT statement

noun

Meaning

The SQL statement that adds one or more new rows to a table, using INSERT INTO followed by the column names and their values.

Where you use it

People say 'insert a row', 'run an INSERT', 'bulk insert' and 'batch inserts'. For large data loads, many rows in one statement or tools like COPY (PostgreSQL) or BULK INSERT (SQL Server) are much faster than inserting rows one by one.

Examples

1. The INSERT statement failed because the email column has a unique constraint.

2. Combine those 10,000 single-row INSERT statements into a few batch inserts.

Common phrases

run an INSERT statement · insert a row · bulk insert · batch insert · INSERT INTO

UPDATE statement

noun

Meaning

The SQL statement that changes values in rows that already exist, usually limited by a WHERE clause so that only the right rows are changed.

Where you use it

Written as UPDATE table SET column = value WHERE condition. Careful teams run the WHERE part as a SELECT first, wrap risky updates in a transaction and check the 'rows affected' count before committing. A mass update on a big table can lock it and fill the log.

Examples

1. I'll run the UPDATE statement inside a transaction and check the row count before I commit.

2. This UPDATE statement should change only the orders from last week.

Common phrases

run an UPDATE statement · UPDATE ... SET · mass update · update a record · rows affected

DELETE statement

noun

Meaning

The SQL statement that removes rows from a table. With a WHERE clause it removes only matching rows; without one it removes every row.

Where you use it

Written as DELETE FROM table WHERE condition. Many systems avoid real deletes and use 'soft delete' instead, setting a deleted_at column. Deleting millions of rows is usually done in small batches to avoid long locks. Do not confuse it with TRUNCATE or DROP.

Examples

1. The cleanup job runs a DELETE statement in batches of 5,000 rows.

2. Always test a DELETE statement on staging before you run it on production.

Common phrases

run a DELETE statement · DELETE FROM · soft delete · delete in batches · hard delete