1830-40; < Neo-LatinPachyderma, assumed singular of Pachydermata (plural) obsolete order name < Greekpachý(s) thick + -dérmata, neuter plural of -dermatos -skinned, adj. derivative of dermat-, stem of dérma skin, derma1
1838, from Fr. pachyderme (c.1600), adopted as a biological term 1797 by Fr. naturalist Georges Léopole Chrétien Frédéric Dagobert, Baron Cuvier (1769-1832), from Gk. pachydermos "thick-skinned," from pachys "thick" (from PIE *bhengh-, cf. Skt. bahu- "much") + derma "skin."