Middle English pier of a bridge, stack, heap, from Middle French pille pier of a bridge, from Latin pila pillar
Noun (3)
Middle English, in plural piles "hair, plumage," borrowed from Anglo-French peil, pil "hair, coat of animal hair, cloth with thick nap" (continental Old French peil, poil "hair"), going back to Latin pilus "hair," of obscure origin
Note: Anglo-French pil for peil, apparently yielding long i in Middle English, is exceptional. The Oxford English Dictionary, third edition, proposes that the word is "partly" borrowed directly from Latin. Middle English Dictionary suggests borrowing from Middle Dutch pijl.
Noun (4)
Middle English pilez, plural, from Medieval Latin pili, perhaps from Latin pila ball