woodlouse vs isopod

woodlouse and isopod both are nouns.

Word	Noun	Adjective	Verb	Adverb
woodlouse	Yes	No	No	No
isopod	Yes	No	No	No

As nouns, isopod is a hypernym of woodlouse; that is, isopod is a word with a broader meaning than woodlouse:

woodlouse: any of various small terrestrial isopods having a flat elliptical segmented body; found in damp habitats
isopod: any of various small terrestrial or aquatic crustaceans with seven pairs of legs adapted for crawling

woodlouse (noun)	isopod (noun)
any of various small terrestrial isopods having a flat elliptical segmented body; found in damp habitats	any of various small terrestrial or aquatic crustaceans with seven pairs of legs adapted for crawling