"male sheep," especially a castrated one, Old English weðer "ram," from Proto-Germanic *wethruz (source also of Old Saxon wethar, Old Norse veðr, Old High German widar, German Widder, Gothic wiþrus "lamb"), literally "yearling," from PIE root *wet- (2) "year" (source also of Sanskrit vatsah "calf," Greek etalon "yearling," Latin vitulus "calf," literally "yearling").