As nouns the difference between seta and spur
is that
seta is a bristle or hair while
spur is a rigid implement, often roughly y-shaped, that is fixed to one's heel for the purpose of prodding a horse. Often worn by, and emblematic of, the cowboy or the knight.
As a verb spur is
to prod (especially a horse) in the side or flank, with the intent to urge motion or haste, to gig.