cork vs plant substance

cork and plant substance both are nouns.

Word	Noun	Adjective	Verb	Adverb
cork	Yes	No	Yes	No
plant substance	Yes	No	No	No

As nouns, plant substance is a hypernym of cork; that is, plant substance is a word with a broader meaning than cork:

Other hypernyms of cork include bark, plant material.

cork (noun)	plant substance (noun)
the plug in the mouth of a bottle (especially a wine bottle)	material derived from plants
a small float usually made of cork; attached to a fishing line
outer bark of the cork oak; used for stoppers for bottles etc.
(botany) outer tissue of bark; a protective layer of dead cells

cork (verb)	plant substance (verb)
stuff with cork
close a bottle with a cork