This meaning refers to flat coverings made from rubber, fabric, straw, foam, or similar material.
Leave your shoes on the mats by the door.
The gym provides exercise mats.
This is the third-person singular form of mat and means causing material to become tangled or compressed together.
Moisture mats the animal's fur.
Sweat mats his hair against his forehead.
This less common verb meaning refers to reducing gloss or creating a matte surface.
The treatment mats the glossy surface.
Fine powder mats the paint finish.