TAST

In linguistics, T_AST (always written as uppercase T plus uppercase AST in subscript) is an abbreviation for the time of assertion, a secondary temporal reference in establishing tense.

Grammatical tense represents the contrast between two measurements along the timeline of an utterance, with one of those measurements being the time of utterance T_UTT (the time at which the actual utterance is made). T_UTT is always the primary point of reference for tense. There are three additional references to which T_UTT can be contrasted: T_AST — the time of assertion, T_COM — the time of completion, and T_EVL — the time of evaluation; these are secondary references. The type used for the secondary reference is determined by aspect and type of utterance.