WordReference Random House Learner's Dictionary of American English © 2025cer•tain /ˈsɜrtən/USA pronunciation
adj.
- free from doubt or reservation;
confident: [be + ~ + (that) clause]I'm certain that I passed the test.[be + ~ + of + verb-ing]She is certain of winning.
- destined;
sure to happen: [be + ~ + to + verb]She is certain to be at the party (= It is sure to happen that she will be at the party).
- bound to come;
that will surely follow and cannot be avoided: War was certain after Germany invaded Poland.
- established as true or sure;
that cannot be argued about: [it + be + ~ + (that) clause]It is certain that you tried.
- trustworthy;
unfailing;
reliable: His aim was certain.
- [before a noun] fixed;
agreed upon;
settled: For a certain amount I can get you across the border.
- [before a noun] (used before a person or thing that is known in the mind of the speaker or writer, but that is being introduced to the listener): A certain Mr. Smith has been trying to meet you.
- [before a noun* a + ~] some though not much;
a kind of: There was a certain reluctance on his part.
pron.
- [~ + of + the + plural noun] some;
particular ones: Certain of the school board members abstained from voting.
Idioms
- Idioms for certain, certainly;
for sure:I didn't know for certain whether I would be hired.
See -cert-.
WordReference Random House Unabridged Dictionary of American English © 2025cer•tain
(sûr′tn),USA pronunciation adj.
- free from doubt or reservation;
confident;
sure:I am certain he will come.
- destined;
sure to happen (usually fol. by an infinitive):He is certain to be there.
- inevitable;
bound to come:They realized then that war was certain.
- established as true or sure;
unquestionable;
indisputable:It is certain that he tried.
- fixed;
agreed upon;
settled:on a certain day; for a certain amount.
- definite or particular, but not named or specified:A certain person phoned. He had a certain charm.
- that may be depended on;
trustworthy;
unfailing;
reliable:His aim was certain.
- some though not much:a certain reluctance.
- [Obs.]steadfast.
- Idioms for certain, without a doubt;
surely:I know for certain that I have seen that face before.
pron.
- certain ones:Certain of the members declined the invitation.
- Vulgar Latin *certānus, equivalent. to Latin cert(us) sure, settled (cer- base of cernere to decide, + -tus past participle suffix) + -ānus -an
- Old French
- Middle English 1250–1300
- 1.See corresponding entry in Unabridged convinced, satisfied. See sure.
- 4.See corresponding entry in Unabridged indubitable, incontestable, irrefutable, incontrovertible, obvious, plain, clear.
- 5.See corresponding entry in Unabridged determined.
Collins Concise English Dictionary © HarperCollins Publishers::
certain / ˈsɜːtən/ - (postpositive) positive and confident about the truth of something; convinced: I am certain that he wrote a book
- (usually postpositive) definitely known: it is certain that they were on the bus
- (usually postpositive) sure; bound; destined: he was certain to fail
- decided or settled upon; fixed: the date is already certain for the election
- unfailing; reliable: his judgment is certain
- moderate or minimum: to a certain extent
- for certain ⇒ definitely; without a doubt
- known but not specified or named: certain people may doubt this
- (as pronoun; functioning as plural): certain of the members have not paid their subscriptions
- named but not known: he had written to a certain Mrs Wong
Etymology: 13th Century: from Old French, from Latin certus sure, fixed, from cernere to discern, decide
'make certain' also found in these entries (note: many are not synonyms or translations):