1. a thickness or layer of a folded or laminated material: "tiles that have a black PVC ply in the lamination"
▪ a strand of yarn or rope: "four-ply yarn"
▪ the number of multiple layers or strands of which something is made: "the yarn can be any ply from two to eight"
▪ a reinforcing layer of fabric in a tyre: "a six-ply whitewall tire"
2. short for plywood
3. (in game theory) the number of levels at which branching occurs in a tree of possible outcomes, typically corresponding to the number of moves ahead (in chess strictly half-moves ahead) considered by a computer program.
▪ a half-move (i.e. one player's move) in computer chess.
Word Originlate Middle English (in the sense ‘fold’): from French pli ‘fold’, from the verb plier, from Latin plicare ‘to fold’.
