plant material vs wood

plant material and wood both are nouns.

Word	Noun	Adjective	Verb	Adverb
plant material	Yes	No	No	No
wood	Yes	No	No	No

As nouns, wood is a hyponym of plant material; that is, wood is a word with a more specific, narrower meaning than plant material:

Other hyponyms of plant material include cutin, chaff, husk, shuck, stalk, straw, stubble, cork, plant product, vegetable tallow.

plant material (noun)	wood (noun)
material derived from plants	any wind instrument other than the brass instruments
	a golf club with a long shaft used to hit long shots; originally made with a wooden head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