Smothered mate is a specific chess technique where a knight delivers checkmate to a king completely surrounded by its own pieces and blocking any escape. Such a mate usually occurs when the king is in a corner of the board or tightly surrounded by its own pawns and pieces resulting in no available moves.
This mate has another name - Lucena's mate (not to be confused with the Lucena position!). Lucena's mate is a classic checkmate position in chess named after the Spanish chess player and theorist Luis Ramirez de Lucena who described it in his book "Repetition of Love and the Art of Chess" (Repeticion de Amores e Arte de Axedrez) published in 1497.