Sack \Sack\ (s[scr]k), n. [OE. seck, F. sec dry (cf. Sp. seco, It. secco), from L. siccus dry, harsh; perhaps akin to Gr. 'ischno`s, Skr. sikata sand, Ir. sesc dry, W. hysp. Cf. {Desiccate}.] A name formerly given to various dry Spanish wines. ``Sherris sack.'' --Shak. {Sack posset}, a posset made of sack, and some other ingredients.