biped (n.)youdaoicibaDictYouDict[biped 词源字典]
"animal with two feet," 1640s, from Latin bipedem (nominative bipes) "two-footed," as a plural noun, "men;" from bi- "two" (see bi-) + pedem (nominative pes) "foot," from PIE root *ped- (1) "a foot" (see foot (n.)).[biped etymology, biped origin, 英语词源]