A spur is a metal instrument composed of a shank, neck, and prick, rowel (sharp-toothed wheel), or blunted end fastened to the heel of a horseman. It is usually used to refine the aids and to back up the natural aids (the leg, seat and voice aids). The spur is used in every equestrian discipline. There are rules in most equestrian organizations about spur use and cruelty issues.

A dressage rider's spur tends to be blunt and shaped so as to give a signal but not cause pain for a horse. Their purpose is not to speed up a horse, but to give him accurate and precise aids in lateral movements or more complicated movements, such as airs above the ground .

The spur's use cannot with certainty be traced further back than Roman times. Early spurs had no neck, a prick being riveted to the shank. Prick spurs had straight necks in the 11th century and bent ones in the 12th. Rowels first appeared early in the 14th. The spurs of medieval knights were gilt and those of esquires silvered. "To win his spurs" meant to gain knighthood.

Derivative meanings

A number of other things are called "spur" by the analogy with the main meaning of the word.

• A spur route in the United States is a branch off a primary Interstate highway that connects with a destination away from the primary route.
• See Spurs for more.

Spur is the official quiz contest of the Iceland School of Commerce.