Rack may refer to any of the following:

• The rack is a torture device.
• A rack and pinion is a certain type of gear used for steering in automobiles.
• A 19-inch rack, in computer terminology, is a standardized system for mounting routers, switches, servers, and various other electronic modules in a vertical, metal frame.
• A rack is a triangular holder used to set up billiard balls
• A rack railway
• In mathematics a rack is an algebraic object used in knot theory
• In oenology, to rack means to transfer a liquid, such as wine, from one container to another by siphoning or pumping, especially to move it away from lees.
• Colloquial and vulgar American English: a woman's breasts, see body parts slang.
• A rack is a set of plastic loops attached to the waistband of a climber's harness for hanging protection equipment on by means of karabiners, or a set of protection equipment for hanging on a rack.