A chessman is one of the playing pieces in chess — a king, queen, bishop, knight, rook (the castle), or pawn. Each side has sixteen, so a full set has thirty-two. The word is a little old-fashioned now. Most people, especially younger players, just say “chess piece,” or they name the piece (“a pawn,” “a knight”). You will still meet chessman in older books and in some dictionaries. The -man here does not mean a male person. It is the old use of man for a piece that stands for a fighter on the board. A queen is still a chessman in this wording, which sounds odd until you know that.

西洋棋棋子（較舊；現在多說 chess piece）