noun, plural cer·tain·ties.

the state of being certain.
something certain; an assured fact.


    for/of a certainty, certainly; without a doubt: I suspect it, but I don't know it for a certainty.

Origin of certainty

1250–1300; Middle English certeinte < Anglo-French, equivalent to certein certain + -te -ty2
Related formsnon·cer·tain·ty, noun, plural non·cer·tain·ties.
Can be confusedcertainty certitude

Synonyms for certainty

Synonym study

1. See belief.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for certainty

Contemporary Examples of certainty

Historical Examples of certainty

  • Well, Shepler might be hurled from that certainty by one hour of determined action.

    The Spenders

    Harry Leon Wilson

  • It was difficult to state with certainty what bad deed she had ever done, or what good deed.


    Thomas Wentworth Higginson

  • Gracie Dennis thought she saw the certainty of failure, and was sorry for it.

  • There was no lessening of the expression of certainty on the young man's face.

    Within the Law

    Marvin Dana

  • Mary's voice came with a certainty of conviction born of fact.

    Within the Law

    Marvin Dana

British Dictionary definitions for certainty


noun plural -ties

the condition of being certain
something established as certain or inevitable
for a certainty without doubt
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for certainty

c.1300, certeynte, "surety, pledge," from Anglo-French certeinté (late 13c.), Old French certainete "certainty," from Latin or Vulgar Latin *certanitatem (source of Old Spanish certanedad); see certain. Meaning "that which is certain" is attested from early 14c.; meaning "quality of being certain" is from mid-14c.

Online Etymology Dictionary, © 2010 Douglas Harper