until
prep.prep. up to a specific time. You use it to show when an action or situation stops.
prep. up to the point in time or the event mentioned. Functions as a temporal marker indicating the terminal point of a continuous action or state.
The shop is open until nine tonight.
We waited at the station until the last train arrived at midnight.
The researchers continued their observations until the battery on the remote sensor finally failed, providing them with three months of uninterrupted data.
From Middle English vntil, until, untill, ontil, ontill, perhaps representing a northern variant of Middle English unto (see Modern English unto). By surface analysis, un- (“against; toward; up to”) + till.
Often shortened to 'till' in informal speech; 'until' is preferred in formal writing and at the start of a sentence.
I will stay here until you will comeI will stay here until you comeIn clauses referring to the future after 'until', use the present simple tense rather than 'will'.