Definitions:
a device with a small spike or a spiked wheel that is worn on a rider's heel and used for urging a horse forward.

a thing that prompts or encourages someone; an incentive

a projection from a mountain or mountain range

a small, single-pointed support for ceramic ware in a kiln.

urge (a horse) forward by digging one's spurs into its sides

give an incentive or encouragement to (someone)

prune in (a side shoot of a plant) so as to form a spur close to the stem