piece: [13] Piece is probably ultimately of Celtic origin. It comes via Anglo-Norman pece from medieval Latin pecia or petia, which appears to have been borrowed from *pettia, an unrecorded word in the Celtic language of ancient Gaul. This would have been descended from an Old Celtic base *pett- that may also be the source of English peat [14]. Anglo-Norman *peche, a variant form of pece, of dialectal origin, gave English patch [14]. => patch, peat
