ranch hand vs cowpoke

ranch hand and cowpoke both are nouns.

Word	Noun	Adjective	Verb	Adverb
ranch hand	Yes	No	No	No
cowpoke	Yes	No	No	No

As nouns, cowpoke is a hyponym of ranch hand; that is, cowpoke is a word with a more specific, narrower meaning than ranch hand:

ranch hand: a hired hand on a ranch
cowpoke: a hired hand who tends cattle and performs other duties on horseback

Other hyponyms of ranch hand include cowhand, cowherd, cowpuncher, puncher.

ranch hand (noun)	cowpoke (noun)
a hired hand on a ranch	a hired hand who tends cattle and performs other duties on horseback