certain

1 of 2

adjective

cer·​tain ˈsər-tᵊn How to pronounce certain (audio)
1
: fixed, settled
a certain percentage of the profit
2
: of a specific but unspecified character, quantity, or degree
the house has a certain charm
3
a
: dependable, reliable
a certain remedy for the disease
b
: known or proved to be true : indisputable
it is certain that we exist
4
a
: inevitable
the certain advance of age
b
: incapable of failing : destined
used with a following infinitive
she is certain to do well
5
: assured in mind or action
I am certain they are right

certain

2 of 2

pronoun

plural in construction
: certain ones
certain of my generationW. B. Yeats
Phrases
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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Adjective
This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. Nc Weather Bot, Charlotte Observer, 8 June 2025 While certain details in specific scenes were modified and some dialogue subtly shifted to enhance the story, the new version follows the original plot’s three-act structure to a tee. Dessi Gomez, Deadline, 8 June 2025 Starting in 2014, Florida universities provided in-state tuition waivers for undocumented students under certain conditions. Clara-Sophia Daly, Miami Herald, 7 June 2025 This would allow operators to fly drones outside their field of view under certain conditions. Will McCurdy, PC Magazine, 7 June 2025 See All Example Sentences for certain

Word History

Etymology

Adjective

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

Pronoun

Middle English certyn, derivative of certeyn certain entry 1

First Known Use

Adjective

13th century, in the meaning defined at sense 1

Pronoun

15th century, in the meaning defined above

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

Browse Nearby Words

Cite this Entry

“Certain.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/certain. Accessed 12 Jun. 2025.

Kids Definition

certain

1 of 2 adjective
cer·​tain ˈsərt-ᵊn How to pronounce certain (audio)
1
: fixed sense 1b
receive a certain share of the profits
2
: not to be doubted : known to be true
it is certain that diamonds are hard
3
: known but not named
a certain person told me
4
: reliable, sure
a certain cure
5
a
: sure to happen : bound to occur : inevitable
defeat was certain
b
: decided in advance by or as if by fate
the plan was certain to succeed
6
: assured in mind or action
feel certain they will come

certain

2 of 2 pronoun
: certain ones
certain of them attended

More from Merriam-Webster on certain

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