octopod vs devilfish

octopod and devilfish both are nouns.

Word	Noun	Adjective	Verb	Adverb
octopod	Yes	No	No	No
devilfish	Yes	No	No	No

As nouns, devilfish is a hyponym of octopod; that is, devilfish is a word with a more specific, narrower meaning than octopod:

octopod: a cephalopod with eight arms but lacking an internal shell
devilfish: bottom-living cephalopod having a soft oval body with eight long tentacles

Other hyponyms of octopod include octopus, Argonaut, Argonauta argo, nautilus, paper nautilus.

octopod (noun)	devilfish (noun)
a cephalopod with eight arms but lacking an internal shell	extremely large pelagic tropical ray that feeds on plankton and small fishes; usually harmless but its size make it dangerous if harpooned
	bottom-living cephalopod having a soft oval body with eight long tentacles
	medium-sized greyish-black whale of the northern Pacific