# anonymous function

CEFR C1 · Compound

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

## Definition

a small piece of computer code that does a job but does not have a name. You use it for quick tasks where you only need the code once.

For teachers: a function definition that is not bound to an identifier. Often used as an argument passed to higher-order functions or for immediate execution in functional programming contexts.

## Examples

- The developer used an anonymous function to sort the list.
- Instead of writing a separate named method, she passed an anonymous function directly into the filter method to process the data.
- In JavaScript, anonymous functions are frequently employed as callbacks to ensure that specific logic executes only after an asynchronous operation, such as a network request, has successfully completed.

## Usage notes

- Commonly referred to as a 'lambda' in many programming languages.

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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.