prep. & conj.
prep. 1 up to or as late as (wait till six o'clock; did not return till night). 2 up to the time of (faithful till death; waited till the end).
conj. 1 up to the time when (wait till I return). 2 so long that (laughed till I cried). ° Until is more usual when beginning a sentence.
[ OE & ON til to, rel. to TILL(3) ]