tetrapod (n.)youdaoicibaDictYouDict[tetrapod 词源字典]
"four-footed animal, quadruped," 1826, from Modern Latin tetrapodus, from Greek tetrapous "four-footed," as a noun, "four-footed animal," from tetra- (see tetra-) + pous "foot," from PIE root *ped- (1) "a foot" (see foot n.)).[tetrapod etymology, tetrapod origin, 英语词源]