Erwan Vallerie ː Penceriac, 861; Penkeriac, 1084; Penkerac, Penheuryaco, 1112; Penchevriac, 1271; Pereac, 1287; Pehereac, XIVvet; Pezerac, XVvet; Pirihac en Guerande, XVIvet; Pihiryat, XVIvet; Pihiriat, XVIvet; Pihiriac, 1566; Piriac, 1630; Pihiriac, 1731;