1. A short spike or spiked wheel that attaches to the heel of a rider's boot and is used to urge a horse forward.
2. Something that serves as a goad or incentive.
3. A spurlike attachment or projection, as:
   1. A spinelike process on the leg of some birds.
   2. A climbing iron; a crampon.
   3. A gaff attached to the leg of a gamecock.
   4. A short or stunted branch of a tree.
   5. A bony outgrowth or protuberance.
4. A lateral ridge projecting from a mountain or mountain range.
5. An oblique reinforcing prop or stay of timber or masonry.
6. Botany. A tubular or saclike extension of the corolla or calyx of a flower, as in a columbine or larkspur.
7. An ergot growing on rye.
8. A spur track.

1. To urge (a horse) on by the use of spurs.
2. To incite or stimulate: "A business tax cut is needed to spur industrial investment" (New York Times).

1. To ride quickly by spurring a horse.
2. To proceed in haste.

[Middle English spure, from Old English spura.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.