ad. At that time: I was still in school then. Come at noon; I'll be ready then. ad. Next in time, space, or order; immediately afterward: watched the late movie and then went to bed. ad. In addition; moreover; besides: It costs $20, and then there's the sales tax to pay. ad. Used after but to qualify or balance a preceding statement: The star was nervous, but then who isn't on the first night of a new play. ad. In that case; accordingly: If traffic is heavy, then allow extra time. ad. As a consequence; therefore: The case, then, is closed. n. That time or moment: The bus leaves at four; until then let's walk. adj. Being so at that time: the then chairman of the board. idiom. then again From another standpoint; on the other hand: I need a vacation. Then again, so do my coworkers.