water hickory vs hickory

water hickory and hickory both are nouns.

Word	Noun	Adjective	Verb	Adverb
water hickory	Yes	No	No	No
hickory	Yes	No	No	No

As nouns, hickory is a hypernym of water hickory; that is, hickory is a word with a broader meaning than water hickory:

water hickory: hickory of southern United States having many narrow leaflets and rather bitter nuts
hickory: American hardwood tree bearing edible nuts

Other hypernyms of water hickory include hickory tree.

water hickory (noun)	hickory (noun)
hickory of southern United States having many narrow leaflets and rather bitter nuts	American hardwood tree bearing edible nuts
	valuable tough heavy hardwood from various hickory trees