# Header Meaning & Pronunciation: Tech English Practice (2026)

> In tech, a header is metadata or information placed at the beginning of a request, response, file, or document that provides instructions or context.

- **Term:** header
- **Part of speech:** noun
- **Pronunciation:** /ˈhedər/
- **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/header
- **Last updated:** 2026-10-27

## Meaning

In tech, a header is metadata or information placed at the beginning of a request, response, file, or document that provides instructions or context. Headers contain key-value pairs that tell systems how to process the data that follows.

Headers appear in multiple tech contexts. In web development, HTTP headers are part of requests and responses that carry information like content type, authentication tokens, and caching rules. In data processing, file headers contain metadata about the file format or structure. In documents and emails, headers are the top sections containing titles or sender information. In tables or spreadsheets, headers are the first row identifying column names. Understanding headers is critical because they control how systems interpret and handle data, making them fundamental to nearly every tech workflow from APIs to databases.

## When you hear it

The API requires specific headers to authenticate your request and process the response correctly.

## Examples

- **in a code review:** "Did you remember to include the Content-Type header in your POST request?"
- **in a standup:** "I spent two hours debugging why the API call failed, then realized I forgot to add the authentication header."
- **in a team meeting:** "We need to document which headers are required and which ones are optional for the new endpoint."

## What native speakers say

- "Set the headers before sending the request"
- "Check the response headers for errors"
- "Add the authorization header to your request"

## Common mistakes

- ✗ "The header is sending in the body of the request." → ✓ "The header is included in the request, not in the body." (Headers are separate from the body; they provide metadata about the request itself, not data within it.)
- ✗ "We forgot to header the request with authentication." → ✓ "We forgot to include the authentication header in the request." (Header is a noun, not a verb in this context. Use include, add, or set with headers.)
- ✗ "The server returned an error in its header." → ✓ "The server returned an error in the response headers." (Headers are typically plural when referring to multiple key-value pairs, or use the singular for a specific header.)

## Be careful

Avoid confusing HTTP headers with document headers or heading styles. Context determines which meaning applies.

## Word forms

| Part of speech | Word | Example |
| --- | --- | --- |
| noun | header | The API request requires an authorization header. |
| noun (plural) | headers | Make sure all the headers are formatted correctly. |
| noun (compound) | header field | The User-Agent header field identifies the client making the request. |


## Collocations

- **set/add/include a header**: These verbs are used to place headers in requests or responses
- **HTTP header**: Most common phrase referring to headers in web communication
- **header value**: The specific data or content assigned to a header key
- **custom header**: Headers that are user-defined rather than standard protocol headers
- **response header**: Headers returned by a server in response to a client request
- **request header**: Headers sent by a client as part of its request to a server

## Synonyms

- **metadata**: Broader term; headers are a specific type of metadata
- **attribute**: General term for properties; less specific than header in tech contexts
- **field**: Used similarly in some contexts but less precise for HTTP communication

## Opposites

- body (the main content after headers)
- payload (the data being sent, distinct from headers)

## Practice

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

## FAQ

### What does header mean in software engineering?

A header is metadata information placed at the beginning of a request, response, file, or document. In HTTP communication, headers are key-value pairs that provide instructions about how to process the data that follows. For example, a Content-Type header tells the system what format the data is in.

### How do you use header in a sentence at work?

You use header as a noun in phrases like: Set the authorization header before sending the request, Check the response headers for error details, or Add a custom header to the API call. Use verbs like set, add, include, or check with headers.

### Is header formal or informal?

Header is neutral in formality. It is equally appropriate in casual standup conversations (Did you add the header?) and formal documentation (The request must include the specified headers). It is a standard technical term used in all professional settings.

### What are the most common headers in web development?

Common headers include Content-Type (specifies data format), Authorization (carries authentication tokens), Accept (tells the server what formats the client accepts), User-Agent (identifies the client), and Cache-Control (controls caching behavior). Each serves a specific purpose in HTTP communication.

### Can header be used as a verb?

In technical English, header is primarily a noun. While some people informally say to header something, the correct usage is to set, add, or include a header. Using header as a verb is considered non-standard and should be avoided in professional settings.


## Related

- [HTTP](https://app.speaktechenglish.com/learn/http.md)
- [API](https://app.speaktechenglish.com/learn/api.md)
- [request](https://app.speaktechenglish.com/learn/request.md)
- [response](https://app.speaktechenglish.com/learn/response.md)
- [payload](https://app.speaktechenglish.com/learn/payload.md)
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