T or t

A point in time or a time interval; frequently a time interval following administration of a drug or the time interval between doses of a drug. The definition of a specific T or t may be explicit or may be inferred from the context in which it is found. Specific times of interest may be indicated by subscripts, e.g., T0 is the time of drug administration; Tn is the time of administration of the nth dose in a series.