maxilliped vs gnathopod

maxilliped and gnathopod both are nouns.

Word	Noun	Adjective	Verb	Adverb
maxilliped	Yes	No	No	No
gnathopod	Yes	No	No	No

As nouns, maxilliped and gnathopod are synonyms defined as:

maxilliped and gnathopod: One of a set of three paired appendages on the thorax of a decapod crustacean, located just posterior to the maxillae and used in feeding.

maxilliped (noun)	gnathopod (noun)
One of a set of three paired appendages on the thorax of a decapod crustacean, located just posterior to the maxillae and used in feeding.	One of a set of three paired appendages on the thorax of a decapod crustacean, located just posterior to the maxillae and used in feeding.