1835 as a type of crustacean having 10 legs, from French décapode (1806), from Modern Latin Decapoda (animalia), from Greek dekapoda, neuter plural of dekapous "ten-footed" (see ten + foot (n.)). From 1888 as a type of locomotive.
Any of various crustaceans of the order Decapoda, characteristically having ten legs, each joined to a segment of the thorax. Crabs, hermit crabs, lobsters, and shrimp are decapods.
A cephalopod mollusk, such as a squid or cuttlefish, having ten armlike tentacles.