Sack1  —n. 1 a large strong bag for storage or conveyance. B quantity contained in a sack. 2 (prec. By the) colloq. Dismissal from employment. 3 (prec. By the) us slang bed. —v. 1 put into a sack or sacks. 2 colloq. Dismiss from employment. [latin saccus] 