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

According to the agency, the EU’s system of geographical indications (GI), which are tags that indicate a product is from a certain region, have played a large part in fostering the imbalance. —Kate Nishimura, Footwear News, 1 May 2026

In a financial environment where nothing feels certain, the ability to convert a lump sum of savings into a predictable monthly check — one that doesn't fluctuate based on what the market is doing — carries real value. —Angelica Leicht, CBS News, 1 May 2026

Becerra proposes to require cities and counties to approve or deny building permits within 90 days, loosening certain regulations for infill projects and reforming construction defect laws to encourage more construction of entry-level condos. —Los Angeles Times, 1 May 2026

All three would go on to represent a certain side of music in the ‘70s, one that had far more to do with old-fashioned pop than with rock. —Brett Milano, Boston Herald, 1 May 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