You use until with a negative to emphasize the moment in time after which the rest of your statement becomes true, or the condition which would make it true. The traffic laws don't take effect until the end of the year. It was not until 1911 that the first of the vitamins was identified.
People often ask which is the correct synonym of until, till, ’til, or ’till? Many assume that till is an abbreviated form of until. In fact, it is a distinct word that existed in English at least a century before until, both as a preposition meaning “to” and as a conjunction meaning “until.”
UNTIL definition: up to the time that or when; till. See examples of until used in a sentence.
Until is often shortened to till or ’til. Till and ’til are more informal and we don’t usually use them in formal writing. Until as a preposition means ‘up to (the time that)’: We played chess until midnight. (up to midnight) The film didn’t end till eleven o’clock.
There is no difference in meaning between until and till. Till is more common in conversation, and is not used in formal writing. If you do something until or till a particular time, you stop doing it at that time. He continued to teach until his death in 1960.
The preposition “until” is a fundamental part of English grammar, crucial for indicating time and duration. Understanding how to use “until” correctly allows you to express when an action or state will continue, cease, or be valid.
USAGE: Until now, so far You usually use until now when a situation has just ended or changed: I have never thought about it until now (=but now I have thought about it).