The term 'Minor Chess Piece' refers to the PAWN, which is a four-letter piece in the game of chess. The PAWN is the weakest and most numerous piece on the board, and it can only move forward one square at a time. It is the only piece that captures differently from how it moves, as it captures diagonally. The PAWN is also the only piece that can be promoted to a higher rank upon reaching the eighth rank.