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." It has seen continuous use in English since the 12th century and is a legitimate synonym of until. 'Til and 'till are much newer words, having appeared as variants of until and till in the 19th and 20th centuries, respectively. 'Till is often rejected, apparently because it seems to have added a superfluous L to the end of until. 'Til, for its part, is typically viewed as inappropriate in formal writing