wheat eel vs roundworm

wheat eel and roundworm both are nouns.

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

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

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

Other hypernyms of wheat eel include nematode, nematode worm.

wheat eel (noun)	roundworm (noun)
small roundworm parasitic on wheat	unsegmented worms with elongated rounded body pointed at both ends; mostly free-living but some are parasitic
	infections of the skin or nails caused by fungi and appearing as itching circular patches