once
adv. freq.adv. one single time. You use this to say that something happened only once and did not repeat.
adv. on one occasion only; a single time. Often used to indicate frequency or to establish a past state in narrative contexts.
I only met him once at a party.
The software requires you to enter the activation code once during the initial setup process.
While the experiment was performed multiple times to ensure accuracy, the specific chemical reaction being studied occurred only once under those exact atmospheric conditions.
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.
Typically placed at the end of a clause or before the main verb. When used to mean 'formerly', it often appears before the verb or adjective it modifies.
I have seen that movie one time.I have seen that movie once.While 'one time' is grammatically correct, 'once' is the standard and more natural adverbial form for expressing a single occurrence.