decapod vs crawdad

decapod and crawdad both are nouns.

Word	Noun	Adjective	Verb	Adverb
decapod	Yes	No	No	No
crawdad	Yes	No	No	No

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

decapod: crustaceans characteristically having five pairs of locomotor appendages each joined to a segment of the thorax
crawdad: small freshwater decapod crustacean that resembles a lobster

Other hyponyms of decapod include crab, lobster, crawdaddy, crawfish, crayfish, hermit crab, shrimp, prawn, tropical prawn.

decapod (noun)	crawdad (noun)
crustaceans characteristically having five pairs of locomotor appendages each joined to a segment of the thorax	small freshwater decapod crustacean that resembles a lobster
cephalopods having eight short tentacles plus two long ones	tiny lobster-like crustaceans usually boiled briefly