# callback

/ˈkɔɫˌbæk/ (US) · /kˈɔːlbæk/ (UK) · CEFR B2 · Noun

Source: https://englishreference.com/word/callback
Updated: 2026-07-22

## Definition

A piece of code you give to a program to run later, usually after it finishes a specific job or when something special happens.

For teachers: A function passed as an argument to another function, intended to be executed after a specific event occurs or an asynchronous task completes. This allows for non-blocking code execution.

## Examples

- The program uses a callback to show a message after the file downloads.
- When the user clicks the button, the browser triggers a callback function to update the screen.
- By passing a callback into the data request, the developer ensures the interface only refreshes once the server responds, though you might also hear the term used for a return phone call.

## Usage notes

- Commonly used in the context of recruitment, performing arts, and telecommunications.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.