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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
When Campbell wasn’t getting offers to walk in certain shows, Evangelista put her foot down. Nina Metz, Chicago Tribune, 20 Sep. 2023 What is certain, however, is that Azerbaijan cannot be trusted with their security. Alex Galitsky, Time, 20 Sep. 2023 Anything the House passes is almost certain to fail in the Senate, meaning negotiations between the two chambers and the White House will be necessary. Grace Segers, The New Republic, 20 Sep. 2023 But from the outset, his family and friends in the local Sikh community were all but certain who was behind the brazen attack: The Indian government of Prime Minister Narendra Modi. Samantha Schmidt, Washington Post, 20 Sep. 2023 There are data wonks like the Entertainment Strategy Guy and the Czech company FlixPatrol that factor in such rankings to determine whether certain shows registered with audiences. Ryan Faughnder, Los Angeles Times, 19 Sep. 2023 Whatever Republicans come up with in the House is nearly certain to be rejected by the Senate, where Democrats and most Republicans together want to fund the government. CBS News, 19 Sep. 2023 As the welcoming committee prepares for the new arrivals, only one thing is certain –this Christmas, Evergreen Lane is going to sleigh! Rebecca Angel Baer, Southern Living, 19 Sep. 2023 But that was nothing compared to the latest 90 Day Fiancé pregnancy, which is certain to cause a range of reactions from viewers. Kelly Wynne, Peoplemag, 19 Sep. 2023 See More

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 30 Sep. 2023.

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 my classmates are absent

More from Merriam-Webster on certain

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