certain

1 of 2

adjective

cer·​tain ˈsər-tᵊn 

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

see also:

for certain of a certain age

certain

2 of 2

pronoun

plural in construction

: certain ones

… certain of my generation …

—W. B. Yeats

Synonyms of certain

Adjective

• one

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

Adjective

Greece temporarily suspended asylum claims from migrants arriving via the Libya route for three months, scrapped certain amnesty provisions and introduced mandatory imprisonment for asylum seekers whose claims are rejected. —Lefteris Pitarakis, Arkansas Online, 1 Mar. 2026

Rather, the company maintains that the technology isn’t ready yet to be deployed responsibly in certain contexts. —Reed Albergotti, semafor.com, 28 Feb. 2026

Greece temporarily suspended asylum claims from migrants arriving via the Libya route for three months, scrapped certain amnesty provisions and introduced mandatory imprisonment for asylum seekers whose claims are rejected. —ABC News, 28 Feb. 2026

In 2021, a federal appeals court affirmed a decision requiring a company in the door manufacturing industry to divest certain assets. —Winston Cho, HollywoodReporter, 28 Feb. 2026

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

Phrases Containing certain

• a certain
• all but certain to
• for certain
• make certain
• make certain of
• of a certain age
• to a certain extent
• under certain circumstances

Rhymes for certain

• bertin
• curtain
• uncertain

Kids Definition

certain

1 of 2 adjective

cer·​tain ˈsərt-ᵊn 

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