"PIE" . . . "?" . _:B2bd9b88975ea7213e3e520128b7d83b7 . "*sér‑o‑ [n.]" . "Etymology for: serum (la1500)" . "*sér‑o‑" . . _:B2bd9b88975ea7213e3e520128b7d83b7 "*sér‑o‑" .