wheat eel vs nematode

wheat eel and nematode both are nouns.

Word	Noun	Adjective	Verb	Adverb
wheat eel	Yes	No	No	No
nematode	Yes	No	No	No

As nouns, nematode is a hypernym of wheat eel; that is, nematode is a word with a broader meaning than wheat eel:

wheat eel: small roundworm parasitic on wheat
nematode: unsegmented worms with elongated rounded body pointed at both ends; mostly free-living but some are parasitic

Other hypernyms of wheat eel include nematode worm, roundworm.

wheat eel (noun)	nematode (noun)
small roundworm parasitic on wheat	unsegmented worms with elongated rounded body pointed at both ends; mostly free-living but some are parasitic