The term ONE OF 16 IN A CHESS SET is a reference to the pieces used in a game of chess. The two crossword solutions for this term are PIECE (5 letters) and PAWN (4 letters). A PIECE is a general term for any of the 16 pieces used in a game of chess, while a PAWN is one of the eight pieces that make up the second row of each player's side. Pawns are the weakest pieces in the game, but they can be promoted to more powerful pieces if they reach the opposite side of the board.