# nonce

> English word · Noun · IPA /nɒns/ · frequency rank #56,938

## Definitions
1. The one or single occasion; the present reason or purpose.
2. A nonce word.
3. A value constructed so as to be unique to a particular message in a stream, in order to prevent replay attacks.

## Etymology
Inherited from Middle English nonse, nones, a rebracketing of Middle English to þen anes, for þen anes (to/for the once (i.e., the one occasion or instance)), from the dative singular neuter of þe. The cryptography sense is commonly said to be a contraction of number used once, although this is probably incorrect.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/nonce