PLY Meaning of PLY in English n. (pl. -ies) 1 a thickness or layer of certain materials, esp. wood or cloth (three-ply). 2 a strand of yarn or rope etc. [ ME f. F pli f. plier, pleier f. L plicare fold ] Concise Oxford English dictionary. Краткий оксфордский словарь английского языка. 2012