corral — “pen” / “yard”
chaps — chaparreras: leg protectors for riding through chaparral
desperado — desesperado (“desperate”)
hackamore — a kind of horse bridle taken from the Spanish jáquima (“halter”)
lasso — lazo (“tie”)
quirt (a short horseman’s whip) — a short horseman’s whip from the Spanish word cuarta (“quarter”)
ranch — rancho (“a very small rural community”)
rodeo — from rodear (“to go around”)
stampede — from estampida
10-gallon hat — from Spanish tan galán (“so gallant”), or possibly galón (“braid”)