This is the 7037th most frequent French word.
mat
Dull or matte (not shiny).
In this context, 'mat' refers to a checkmate in the game of chess, the final move that defeats the opponent.
Le joueur d'échecs posa son dernier coup, donnant un mat imparable.
The chess player made his last move, delivering an unstoppable checkmate.
Here, 'mat' again describes a dull, non-reflective quality of the morning light.
La lumière matinale avait un éclat doux et mat.
The morning light had a soft and matte glow.
Here, 'mat' describes an unshiny, matte surface texture of the carpet.