until

until, till

1. Till is not a shortened form of until but is the older word; the un- of until adds the element ‘up to, as far as’. The two words can both be used as prepositions (e.g. until/till tomorrow) or conjunctions (e.g. until/till we reach home) They are largely interchangeable, except that until is more usual at the beginning of a sentence and can sound somewhat more formal, especially in speech:

• He didn't ask any more questions but he kept himself awake till Noreen came home —Ann Pilling, 1987

• Until he got Jackson's note he had been convinced that the man was suffering from some sort of regular illness —C. Horrie et al., 1988

• They say they don't trust him, until he looks them in the eye —Scotland on Sunday, 2004.

2. Up until and up till are needless variants in which the word up is usually redundant and (especially with until) awkward: The fast-growing food-supplement market, in particular that for vitamins, which up till now [read: till now or up to now]

• has largely remained in the hands of smaller companies —Ecologist, 2001

• My dad had a stammer up until he was 18 [read: until he was 18 or up to the age of 18] —London Review of Books, 2003.

3. See also unless and until.

4. Until such time as can be effective in emphasizing uncertainty about the outcome, but it should not be made to serve as a more verbose alternative to the simple word until:

• Such noisy groups of youngsters…need to be broken down into smaller groups each controlled by a responsible competent leader or instructor until such time as they become mature canoeists —Canoeist, 1991.