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cer·​tain ˈsər-tᵊn How to pronounce certain (audio)
: fixed, settled
a certain percentage of the profit
: of a specific but unspecified character, quantity, or degree
the house has a certain charm
: dependable, reliable
a certain remedy for the disease
: known or proved to be true : indisputable
it is certain that we exist
: inevitable
the certain advance of age
: incapable of failing : destined
used with a following infinitive
she is certain to do well
: assured in mind or action
I am certain they are right


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plural in construction
: certain ones
certain of my generationW. B. Yeats
for certain
: as a certainty : assuredly
the cause is not known for certain
of a certain age
: of a somewhat advanced age : no longer young
remembered by people of a certain age
Choose the Right Synonym for certain

sure, certain, positive, cocksure mean having no doubt or uncertainty.

sure usually stresses the subjective or intuitive feeling of assurance.

felt sure that I had forgotten something

certain may apply to a basing of a conclusion or conviction on definite grounds or indubitable evidence.

police are certain about the cause of the fire

positive intensifies sureness or certainty and may imply opinionated conviction or forceful expression of it.

I'm positive that's the person I saw

cocksure implies presumptuous or careless positiveness.

you're always so cocksure about everything

Examples of certain in a Sentence

Adjective I'm fairly certain that I'll be on time. a certain person told me that today is your birthday
Recent Examples on the Web
For gaming, Perri attaches 14 electrodes to her scalp that read her brain’s reaction to specific thoughts to initiate cognitive activity, as well a pair of EEG earbuds that register pulsing of her ear muscles to get a more direct physical response for certain actions. Christopher Cruz, Rolling Stone, 10 July 2024 Against that backdrop, and rapid election staff turnover, the county elections department has also made certain administrative mistakes, like sending mail ballots to voters who had opted out of receiving them and misprinting certain local sample ballots, though none that affect tabulation. CBS News, 10 July 2024 The prosecution and defense made arguments on various motions to preclude certain evidence and testimony from being admitted at trial. Charna Flam, Peoplemag, 10 July 2024 In the upper peninsula, officials would reinstate coyote season year-round, allow antlerless deer to be hunted with archery equipment only, eliminate antlerless permits in certain regions, enact a three point restriction and create hunter safety courses for local schools. Carly Moran | The Center Square, Washington Examiner - Political News and Conservative Analysis About Congress, the President, and the Federal Government, 10 July 2024 See all Example Sentences for certain 

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'certain.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History



Middle English certeyn, certayne, borrowed from Anglo-French certein, certain, going back to Vulgar Latin *certānus, from Latin certus "fixed, settled, indisputable," originally past participle of cernere "to sift, discern, decide, determine" (going back to an Indo-European present stem *kri-n-, verbal adjective *kri-to-, from a verbal base *krei̯̯̯(h1)- "sift, separate," whence Greek krī́nein "to separate, choose, decide," verbal adjective kritós, Welsh gogrynu "to sift") + -ānus + -an entry 2


Middle English certyn, derivative of certeyn certain entry 1

First Known Use


13th century, in the meaning defined at sense 1


15th century, in the meaning defined above

Time Traveler
The first known use of certain was in the 13th century

Dictionary Entries Near certain

Cite this Entry

“Certain.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/certain. Accessed 24 Jul. 2024.

Kids Definition


1 of 2 adjective
cer·​tain ˈsərt-ᵊn How to pronounce certain (audio)
: fixed sense 1b
receive a certain share of the profits
: not to be doubted : known to be true
it is certain that diamonds are hard
: known but not named
a certain person told me
: reliable, sure
a certain cure
: sure to happen : bound to occur : inevitable
defeat was certain
: decided in advance by or as if by fate
the plan was certain to succeed
: assured in mind or action
feel certain they will come


2 of 2 pronoun
: certain ones
certain of them attended

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