eelworm vs nematode

eelworm and nematode both are nouns.

Word	Noun	Adjective	Verb	Adverb
eelworm	Yes	No	No	No
nematode	Yes	No	No	No

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

eelworm: any of various small free-living plant-parasitic roundworms
nematode: unsegmented worms with elongated rounded body pointed at both ends; mostly free-living but some are parasitic

Other hypernyms of eelworm include nematode worm, roundworm.

eelworm (noun)	nematode (noun)
any of various small free-living plant-parasitic roundworms	unsegmented worms with elongated rounded body pointed at both ends; mostly free-living but some are parasitic