DictionaryAI

nonce

USNAHNS/nɑns/SayNONSUK/nɒns//nɔns/

Pluralnonces

7 meanings of nonce

Practice

  1. 1
    computer securitynouncountable
    In cryptography, a number or value used only once in a communication, for example so that an old message cannot be replayed or so that each encryption is unique.

    The server rejects any request whose nonce it has already seen, blocking replay attacks.

    Reusing a nonce with the same key can expose the contents of encrypted messages.

    Note

    Cryptographers often explain the word as number used once, a handy memory aid but probably not the real origin: it is the old nonce of the single occasion, and Roger Needham and Michael Schroeder's 1978 paper on authentication glosses it simply as "used only once". What defines a nonce is uniqueness. Some schemes keep it secret, but in encryption modes such as CCM and GCM it can be public and must simply never repeat under the same key.

    Checked 1 Nov 2026 · 8 facts

    • “Number used once” is a common explanation, but the cryptographic term probably derives from the older nonce meaning a single occasion. en.wiktionary.org
    • Roger Needham and Michael Schroeder jointly wrote the authentication paper. bitsavers.trailing-edge.com
    • The paper was published in 1978. microsoft.com
    • The paper explicitly glosses nonce as “used only once”. ptacts.uspto.gov
    • A nonce is defined by non-repetition within its relevant context. csrc.nist.gov
    • Some cryptographic schemes use secret nonces. csrc.nist.gov
    • Nonces used with authenticated encryption, including CCM and GCM, can be public. rfc-editor.org
    • CCM and GCM require nonce values to be unique under a given encryption key. datatracker.ietf.org
  2. 2
    for nownounliterary
    The one particular occasion, or the present purpose, now heard only in the phrase for the nonce.

    The committee agreed to keep the current rules for the nonce and revisit them in the spring.

    For the nonce, he was content to let his rival take the credit.

    UsageFor the nonce sounds bookish; in everyday speech, for now is the usual choice.

    Note

    The n was borrowed from a neighbor: Middle English said for then anes, "for the once", and the n of the old article slid onto the next word. The phrase is now fixed, with a slightly literary ring, but other frames were once possible: Browning's Childe Roland to the Dark Tower Came (1855) has its narrator scold himself for dozing "at the very nonce".

    Checked 3 Nov 2026 · 5 facts

    • Middle English had for then anes, meaning "for the once". en.wiktionary.org
    • The initial n of nonce came from redivision of the preceding article. en.wiktionary.org
    • Robert Browning wrote Childe Roland to the Dark Tower Came, first published in 1855. en.wikipedia.org
    • Nonce formerly occurred in constructions other than for the nonce. en.wikisource.org
    • The poem's narrator scolds himself for dozing, using the exact words "at the very nonce". rpo.library.utoronto.ca
  3. 3
    nouncountable
    In lexicography, a nonce word: a word coined for a single occasion or use.
    Note

    Lexicographers use the bare noun as shorthand for nonce word, and the label is always provisional. A coinage that becomes established has stopped being a nonce and joined the ordinary vocabulary, so an editor who calls something a nonce is really saying it has not yet caught on beyond the occasion it was made for.

    Checked 31 Oct 2026 · 1 fact

    • Limited repetition or adoption does not necessarily establish a coinage in ordinary vocabulary; nonce words can achieve repeated use within a small group. en.wikipedia.org
  4. 4
    adjective
    Made or used for a single occasion or purpose, or happening only once.

    The interviews contained many nonce borrowings, each occurring only once.

    The poet's nonce coinages rarely outlive the poem they were written for.

    Similarone-off

  5. 5
    sex offendernounderogatoryBritishIrelandcountable
    A derogatory term for a sex offender, especially one who has committed sexual offenses against children.
    Note

    This is a separate word from the "one occasion" noun: it surfaced in British criminal slang in the 1970s, and none of its proposed origins has been proved. Prison is its home ground, where the nonce wing holds offenders against children apart, protected from the other prisoners.

    Checked 31 Oct 2026 · 4 facts

  6. 6
    stupid personnounslangderogatoryBritishIrelandcountable
    A person regarded as stupid or worthless.

    Don't be such a nonce, the train leaves from the other platform.

    Some nonce left the gate open and the dog got out.

    UsageEven as banter it can be heard as an accusation of sexual offenses, so it is best avoided.

    Similaridiot, prat, plonker, muppet

    Note

    The milder insult probably grew out of the word for a sex offender rather than the other way round, and the harsher meaning is never far off.

    Checked 2 Nov 2026 · 1 fact

    • The milder insult probably developed from the sexual-offender term; the reverse development is unproved. en.wiktionary.org

Less common meaning

  1. 7
    nounslangBritishIreland
    Someone who informs to the police and so betrays a criminal enterprise.

Practice

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Origins

Meanings 1–4

Middle English had the phrases to þen anes and for þen anes ("to/for the once", meaning the one occasion or instance), where þen is the dative singular neuter of þe. Splitting these words in a new place produced nonse or nones, which passed down into modern English. People often say the cryptography sense is short for number used once, but that is probably wrong.

Checked 1 Nov 2026 · 6 facts

  • Middle English had the phrases to þen anes and for þen anes. en.wiktionary.org
  • The phrases literally meant to/for the once, referring to one occasion or instance. en.wiktionary.org
  • Þen is the dative singular neuter form of þe. en.wiktionary.org
  • Rebracketing produced Middle English nonse or nones, inherited as modern English nonce. en.wiktionary.org
  • The cryptography term is often explained as short for number used once. developer.mozilla.org
  • The explanation number used once is probably not the historical origin of the cryptography term. en.wikipedia.org
Meanings 5–6

This is British criminal slang recorded by 1970, and its origin is unknown. One possible source is dialect nonce or nonse, meaning a stupid or worthless person, though that use cannot be shown to be earlier. Another possibility is nance, meaning an effeminate or homosexual man, from nancy or nancyboy. People have also pointed out that it rhymes with ponce. The prison explanation "Not On Normal Communal Exercise" was probably invented later to fit the existing word.

Checked 1 Nov 2026 · 7 facts