a framework of bars, wires, or pegs on which articles are arranged or deposited: a clothes rack; a luggage rack.
a fixture containing several tiered shelves, often affixed to a wall: a book rack; a spice rack.
a spreading framework set on a wagon for carrying hay, straw, or the like, in large loads.
Pool. a wooden frame of triangular shape within which the balls are arranged before play. the balls so arranged: He took aim at the rack.
Machinery. a bar, with teeth on one of its sides, adapted to engage with the teeth of a pinion (rack and pinion) or the like, as for converting circular into rectilinear motion or vice versa. a bar having a series of notches engaging with a pawl or the like.