Definition:Chess/Pawn/Promotion

Definition
If a pawn moves onto the square on the final rank, it is then exchanged for any other type of piece which replaces the pawn on that square.

This is called promotion.

The player of that pawn decides which piece to replace it with, which may be neither another pawn nor a king.

If it is promoted to a queen (which is usual, the queen being the most powerful piece), this operation is colloquially referred to as queening.