hickory vs wood

hickory and wood both are nouns.

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

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

hickory (noun)	wood (noun)
American hardwood tree bearing edible nuts	any wind instrument other than the brass instruments
valuable tough heavy hardwood from various hickory trees	a golf club with a long shaft used to hit long shots; originally made with a wooden head
	the trees and other plants in a large densely wooded area
	the hard fibrous lignified substance under the bark of trees