vaquero vs cowhand

vaquero and cowhand both are nouns.

Word	Noun	Adjective	Verb	Adverb
vaquero	Yes	No	No	No
cowhand	Yes	No	No	No

As nouns, cowhand is a hypernym of vaquero; that is, cowhand is a word with a broader meaning than vaquero:

vaquero: local names for a cowboy (`vaquero' is used especially in southwestern and central Texas and `buckaroo' is used especially in California)
cowhand: a hired hand who tends cattle and performs other duties on horseback

Other hypernyms of vaquero include cowherd, cowpoke, cowpuncher, puncher.

vaquero (noun)	cowhand (noun)
local names for a cowboy (`vaquero' is used especially in southwestern and central Texas and `buckaroo' is used especially in California)	a hired hand who tends cattle and performs other duties on horseback