octopod vs cephalopod

octopod and cephalopod both are nouns.

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

As nouns, cephalopod is a hypernym of octopod; that is, cephalopod is a word with a broader meaning than octopod:

octopod: a cephalopod with eight arms but lacking an internal shell
cephalopod: marine mollusk characterized by well-developed head and eyes and sucker-bearing tentacles

Other hypernyms of octopod include cephalopod mollusk.

octopod (noun)	cephalopod (noun)
a cephalopod with eight arms but lacking an internal shell	marine mollusk characterized by well-developed head and eyes and sucker-bearing tentacles

octopod (adjective)	cephalopod (adjective)
	relating or belonging to the class Cephalopoda