any of various portable devices for raising or lifting heavy objects short heights, using various mechanical, pneumatic, or hydraulic methods.
(initial capital letter) Informal. fellow; buddy; man (usually used in addressing a stranger): Hey, Jack, which way to Jersey?
Also called jackstone. Games. one of a set of small metal objects having six prongs, used in the game of jacks. one of any other set of objects, as pebbles, stones, etc., used in the game of jacks. jacks, (used with a singular verb) a children's game in which small metal objects, stones, pebbles, or the like, are tossed, caught, and moved on the ground in a number of prescribed ways, usually while bouncing a rubber ball.