once
adv. · conj. · n.-
1 one time only (adv.) A1 Beginnerone time and only one time.
on a single occasion; one time only.
ExampleI have only been to Paris once, but I would love to go back.
ExampleThe medication should be administered once every twenty-four hours to maintain a consistent level in the bloodstream.
UsageUsually placed after the verb or at the end of a clause.
- once only
- singly
-
2 in the past (adv.) A2 Elementaryat a time in the past but not anymore.
at a former time; formerly.
ExampleThis building was once a school, but now it is a library.
ExampleThe region was once a thriving industrial hub, though it has since transitioned into a service-based economy.
UsageOften used to introduce stories or to describe a state that has changed.
Show 3 more sensesShow fewer
-
3 multiplied by one (adv.) B2 Upper Intermediate Technical Mathmultiplied by the number one.
indicating that a quantity is multiplied by one.
ExampleAny number multiplied once by itself remains the same.
ExampleThe formula requires the variable to be factored once before the final calculation is performed.
UsageUsed in mathematical contexts to define identity or frequency.
-
4 as soon as (conj.) B1 Intermediateas soon as or after something happens.
as soon as; at the moment that.
ExampleOnce you finish your homework, you can go outside and play.
ExampleOnce the contract has been signed by both parties, the initial deposit will be transferred to the escrow account.
UsageUsed to join two clauses; the 'once' clause usually happens first.
-
5 fan of the band Twice (n.) C1 Advanced Slang Musica name for a fan of the famous music group called Twice.
a member of the official fandom for the South Korean girl group Twice.
ExampleShe has been a dedicated Once since the band first started.
ExampleThousands of Onces gathered outside the stadium hours before the concert began, trading photocards and singing along to the group's latest hits.
Teacher's tipThis is a very specific cultural term used by fans of K-pop; it is not used in general or formal English.
From Middle English ones, from Old English ānes, a remodelling (after ān (“one”)) of ǣnes, itself an extension of ǣne (“once”) with the genitive suffix -es. Equivalent to one + -s. Cognate with Saterland Frisian enst, insen (“once”), West Frisian iens (“once”), Dutch eens (“once”), German Low German eens, ins (“once”), German einst (“once”). More at one (including regarding the development of the pronunciation) and -s.