# undefined

/ˌəndɪˈfaɪnd/ (US) · /ˌʌndɪfˈaɪnd/ (UK) · CEFR B2 · Adjective

Source: https://englishreference.com/word/undefined
Updated: 2026-05-11

## Definition

not having a clear meaning, limit, or description. In math or computer code, it describes something that has no value or has not been explained yet.

For teachers: lacking a precise explanation, boundary, or definition. In technical contexts, it refers to a variable or expression that has not been assigned a value or whose value is mathematically impossible to determine.

## Examples

- The rules of the game remain undefined for now.
- The program crashed because it tried to access an undefined variable that had no data assigned to it.
- While the legal framework for the new territory is still largely undefined, local authorities are operating under a temporary set of guidelines to maintain order.

## Usage notes

- Often follows a linking verb like 'be', 'remain', or 'stay'. In computing, it is frequently used as a technical state rather than just a descriptive quality.

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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.