# Environment Variable in English: Common Mistakes to Avoid (2026)

> A named value that your operating system or application stores and passes to running programs.

- **Term:** environment variable
- **Part of speech:** noun
- **Pronunciation:** /ɪnˈvaɪrənmənt ˈvɛriəbəl/
- **English level (CEFR):** B2
- **Register:** Neutral, Both
- **Region:** US and UK
- **Topic:** [Tech jargon](https://app.speaktechenglish.com/learn/topics/tech-jargon.md)
- **Lesson:** https://app.speaktechenglish.com/learn/environment-variable
- **Last updated:** 2026-10-27

## Meaning

A named value that your operating system or application stores and passes to running programs. Environment variables hold configuration data like file paths, API keys, or database URLs that programs need without hardcoding them.

Environment variables are key-value pairs stored at the system or application level that programs read when they start. For example, your PATH environment variable tells your computer where to find executable programs, and a DATABASE_URL variable might tell your app which database to connect to. In tech teams, developers use environment variables to keep sensitive information (like API keys) and configuration details out of source code. This is especially important because you can set different values for development, testing, and production environments without changing the actual code. When you set an environment variable like export API_KEY=abc123 in your terminal, any program launched from that terminal session can access it.

## When you hear it

Before deploying to production, make sure all your environment variables are properly configured.

## Examples

- **in a standup:** "We moved the database connection string to an environment variable so different team members can use their own local databases."
- **in a code review:** "Good catch—we should never hardcode the API key in the source. Let's use an environment variable instead."
- **in a team meeting:** "The deployment failed because the REDIS_URL environment variable was not set on the staging server."

## What native speakers say

- "We store sensitive data in environment variables"
- "Set the environment variable before running the script"
- "Check if the environment variable is defined"

## Common mistakes

- ✗ "I need to environment variable this value." → ✓ "I need to store this value in an environment variable." (Environment variable is a noun, not a verb. You store or set environment variables, but you do not environment variable something.)
- ✗ "We use environment variables for all our variables in the code." → ✓ "We use environment variables for configuration data and sensitive information." (Environment variables are specifically for OS or system-level configuration, not for every variable in your code.)
- ✗ "The environment variable is stored in the source code repository." → ✓ "The environment variable is stored in the operating system or a .env file, not in the repository." (Environment variables should be kept separate from code for security and flexibility reasons.)

## Be careful

Often confused with local variables or parameters. Do not use it to refer to any variable in code—it specifically means system-level or OS-level configuration values.

## Word forms

| Part of speech | Word | Example |
| --- | --- | --- |
| noun | environment variable | Set the environment variable before deploying. |
| noun (plural) | environment variables | We use environment variables to configure our microservices. |
| adjective (modifier) | environment variable | The environment variable value was incorrect. |


## Collocations

- **set an environment variable**: To assign or create an environment variable with a value
- **define an environment variable**: To specify what an environment variable should be
- **read an environment variable**: To access or retrieve the value stored in an environment variable
- **export an environment variable**: To make an environment variable available to child processes
- **environment variable is not set**: When an environment variable does not exist or has no value

## Synonyms

- **env var**: Informal abbreviation, used in casual conversation and documentation
- **configuration variable**: Broader term that can include environment variables and other config settings
- **system variable**: Specifically refers to variables managed by the operating system

## Opposites

- hardcoded value
- local variable
- inline parameter

## Practice

This lesson has 4 practice exercises with instant feedback on the page: https://app.speaktechenglish.com/learn/environment-variable

## FAQ

### What is the main purpose of environment variables?

Environment variables store configuration data that programs need when they run. They allow you to change settings without modifying source code, and they keep sensitive information like API keys and passwords out of your repository. This makes it easy to use different settings for development, testing, and production.

### How do you set an environment variable on different operating systems?

On Linux and Mac, use export VAR_NAME=value in the terminal or add it to your .bashrc or .zshrc file. On Windows, use set VAR_NAME=value in Command Prompt or setx VAR_NAME value to make it permanent. Many developers use a .env file with tools like dotenv to manage variables across all systems.

### Why should you not put environment variables in your source code?

Hardcoding sensitive data like API keys or passwords in your code is a serious security risk. If your code is shared publicly or uploaded to version control, anyone can see those secrets. Environment variables keep this information separate and secure, and allow different team members to use different values for their local development.

### Is environment variable formal or informal language?

Environment variable is neutral and professional language used in all tech contexts—code reviews, documentation, meetings, and interviews. It is not slang, so it is appropriate for formal presentations, but it is also common in casual team conversations. The abbreviation env var is more informal.


## Related

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