cer·tain | \ ˈsər-tᵊn \

Definition of certain 

(Entry 1 of 2)

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

3a : dependable, reliable a certain remedy for the disease

b : known or proved to be true : indisputable it is certain that we exist

4a : 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

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

Definition of certain (Entry 2 of 2)

: certain ones certain of my generation —W. B. Yeats

Keep scrolling for more

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


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

Neuropsychological assessments are a specialized form of psychological testing that sees how certain neurological conditions affect mental health and the nervous system. Michelle Mullins, Naperville Sun, "Naperville People in the News," 13 July 2018 The new law left many citizens confused as to who had access to certain areas of the beach. Jacob Sweet, miamiherald, "Contradicting law he signed, Gov. Rick Scott orders that Florida beaches be kept open to public," 12 July 2018 But the stress and pressure of trying to breastfeed, at a certain point, might not be great for your mental health, so stopping altogether might be necessary, and that's OK. Korin Miller, SELF, "Khloé Kardashian Says She Had to Stop Breastfeeding After Two Months," 11 July 2018 The results also revealed that people are more likely to overlook certain areas of their face, like the eyelids, when applying SPF moisturizer. Tess Garcia, Teen Vogue, "Study Determines SPF Moisturizers Are Less Effective Than Sunscreen," 8 July 2018 At a certain point, Sharp Objects is a victim of its own prescience. Vogue, "Is Sharp Objects the Next Big Little Lies?," 3 July 2018 The new rule is also certain to get challenged in court, eventually giving the Supreme Court an opportunity to rule on the Trump EPA’s more narrow interpretation. Emily Atkin, The New Republic, "How the New Supreme Court Could Halt Climate Action," 12 July 2018 Still, Rogge and other researchers couldn’t say for certain what in the mussels would sicken the dogs. Tim Prudente, baltimoresun.com, "Explosion of false dark mussels revives hopes for clearer waters and concern for dogs in Anne Arundel County," 11 July 2018 Worse still, the problem is almost certain to grow substantially. Michael Hicks, Indianapolis Star, "Hicks: Finally, a government answer to job losses caused by automation," 8 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'certain.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of certain


13th century, in the meaning defined at sense 1

Pronoun, plural in construction

15th century, in the meaning defined above

History and Etymology for certain


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, plural in construction

Middle English certyn, derivative of certeyn certain entry 1 — see certain entry 1

Keep scrolling for more

Learn More about certain

Statistics for certain

Last Updated

13 Sep 2018

Look-up Popularity

Time Traveler for certain

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

See more words from the same century

Keep scrolling for more

More Definitions for certain



English Language Learners Definition of certain

: not having any doubt about something : convinced or sure

—used with it to say that something is known to be true or correct

—used to refer to something or someone that is not named specifically


cer·tain | \ ˈsər-tᵊn \

Kids Definition of certain

 (Entry 1 of 2)

1 : without any doubt : sure Are you certain you saw her?

2 : known to be true It's certain that they were here.

3 : known but not named A certain person told me.

4 : being fixed or settled a certain percentage of the profit

5 : bound by the way things are Our plan is certain to succeed.

6 : sure to have an effect a certain cure



Kids Definition of certain (Entry 2 of 2)

: known ones that are not named Certain of the students could work harder.

Keep scrolling for more

Comments on certain

What made you want to look up certain? Please tell us where you read or heard it (including the quote, if possible).


to make amends

Get Word of the Day daily email!

Test Your Vocabulary

Musical Words Quiz

  • gramophone
  • Which word describes a musical performance marked by the absence of instrumental accompaniment?
True or False

Test your knowledge - and maybe learn something along the way.

Syn City

Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!