isopod vs wood louse

isopod and wood louse both are nouns.

Word	Noun	Adjective	Verb	Adverb
isopod	Yes	No	No	No
wood louse	Yes	No	No	No

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

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

Other hyponyms of isopod include slater, woodlouse, sea louse, sea slater.

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