'til
prep. A2 Elementary US //ˈtɪɫ// UK //tˈɪl// til
prep. up to a certain time. It is a shorter, more casual way to say 'until'.
prep. up to the point in time or the event mentioned. An informal contraction of 'until', often used in speech and casual writing.
From a misunderstanding of till as an aphetic form of until.
Usage
Often written with a leading apostrophe to indicate the missing letters from 'until', though 'till' is a separate, older alternative.
Pitfall
I waited til he arrived.I waited 'til he arrived.In formal writing, 'til should include an apostrophe to show it is a contraction of 'until', though 'till' (with two Ls) is also a correct standalone word.