from The American Heritage® Dictionary of the English Language, 4th Edition

  • adj. Definite; fixed: set aside a certain sum each week.
  • adj. Sure to come or happen; inevitable: certain success.
  • adj. Established beyond doubt or question; indisputable: What is certain is that every effect must have a cause.
  • adj. Capable of being relied on; dependable: a quick and certain remedy.
  • adj. Having or showing confidence; assured.
  • adj. Not specified or identified but assumed to be known: felt that certain breeds did not make good pets.
  • adj. Named but not known or previously mentioned: a certain Ms. Johnson.
  • adj. Perceptible; noticeable: a certain charm; a certain air of mystery.
  • adj. Not great; calculable: to a certain degree; a certain delay in the schedule.
  • pro. An indefinite but limited number; some: Certain of the products are faulty.
  • idiom for certain Without doubt; definitely.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Sure, positive, not doubting.
  • Having been determined but unspecified. The quality of some particular subject or object which is known by the speaker to have been specifically singled out among similar entities of its class.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Assured in mind; having no doubts; free from suspicions concerning.
  • adj. Determined; resolved; -- used with an infinitive.
  • adj. Not to be doubted or denied; established as a fact.
  • adj. Actually existing; sure to happen; inevitable.
  • adj. Unfailing; infallible.
  • adj. Fixed or stated; regular; determinate.
  • adj. Not specifically named; indeterminate; indefinite; one or some; -- sometimes used independenty as a noun, and meaning certain persons.
  • adv. Certainly.
  • n. Certainty.
  • n. A certain number or quantity.

from The Century Dictionary and Cyclopedia

  • Fixed; determinate; definite; specified; prescribed; settled beforehand: as in the phrase “at a time certain.”
  • Indefinite in the sense of not being specifically named; known but not described: applied to one or more real individual objects or characters, as distinguished from a class of objects or an order of characters; coming under particular observation, but undefined, as to kind, number, quantity, duration, etc.; some particular: as, a lady of a certain age.
  • Some (known but unspecified): followed by of.
  • Established as true or sure; placed beyond doubt; positively ascertained and known; unquestionable; indisputable.
  • Capable of being depended on; trustworthy.
  • Unfailing; unerring; sure; positive: as, a certain remedy for rheumatism.
  • Assured; free from doubt regarding: used absolutely, or with of, and formerly sometimes with on.
  • Sure: with an infinitive: as, he is certain to be there to-morrow.
  • Synonyms Undeniable, unquestionable, undoubted, indubitable, indisputable, incontrovertible, inevitable. Sure, Positive, Certain, Confident, etc. (see confident); unhesitating, undoubting.
  • n. A definite but unstated quantity.
  • n. Certainty.
  • n. In the Roman Catholic Church, prayers said daily at mass for specified persons, as for the members of a guild unable to keep a priest of its own, but who paid so much to a church to have a daily remembrance. Also certainty.
  • Certainly; assuredly.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adj. exercising or taking care great enough to bring assurance
  • adj. reliable in operation or effect
  • adj. having or feeling no doubt or uncertainty; confident and assured
  • adj. certain to occur; destined or inevitable
  • adj. definite but not specified or identified
  • adj. established beyond doubt or question; definitely known
  • adj. established irrevocably


from The American Heritage® Dictionary of the English Language, 4th Edition

Middle English, from Old French, from Vulgar Latin *certānus, from Latin certus, past participle of cernere, to determine.

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Middle English certain, certein, from Old French certain, from Vulgar Latin unattested form *certānus, extended form of Latin certus ("fixed, resolved, certain"), of the same origin as cretus, past participle of cernere ("to separate, perceive, decide"). Displaced native Middle English wis, iwis ("certain, sure") (from Old English, ġewiss ("certain, sure") and alternative Middle English spelling sertane ("some, certain")


  • However, you should note that many of the compilers (language processors) and commands on the PRIME will make certain assumptions if you follow certain guidelines.

    Phrack Issue #15 Elric of Imrryr's Issue

  • [Footnote 1: «qua» is generally used instead of «quae» in the feminine nominative singular and in the neuter nominative and accusative plural.] «485. » «quīdam», _a certain one, a certain_

    Latin for Beginners

  • "I am terrified to say such a thing, but I am certain, quite _certain_, that the ship will be lost within the next few days."

    The Stowaway Girl

  • We can honor him, in certain ways -- in _certain_ ways, Raoul -- almost more than if he had never done wrong at all.

    The Inner Shrine

  • Which certain people call a "_certain age_," [205]

    The Works of Lord Byron. Vol. 4

  •  certain stresses and certain environmental conditions, would never have re - sulted in this behavior but did.


  • "Yes, I have at my command one method that is certain, -- _perfectly certain_.

    Fairy Fingers A Novel

  • Asked what Kan meant by the term "certain progress," Noda said, "that's something that Kan said, so please ask him."

    Japan PM Strongly Attacked, Lukewarmly Defended, Over Resignation Plans

  • It's the certain in the phrase "certain tax preparers" that's still causing controversy. News

  • When we label certain kinds of books "boy books" we are not only reinforcing a certain idea of manliness that doesn't include all boys, we are also cutting boys and girls off from a lot of books they might actually like.

    Charles London: There Are No Boy Books


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  • A contranym: both an indeterminate quality ("she has a certain air about her"), and an established fact (a certainty).

    May 15, 2008