means Having a dull, non-reflective surface or finish, free of shine or gloss.

from From French mat, 'dull, dead, lusterless,' which traces back to Latin mattus, meaning 'sodden' or 'drunk' — possibly related to the verb madēre, 'to be wet.' The notion seems to have drifted from a heavy, sodden dullness to the visual dullness of a surface that doesn't gleam. The same French root also gives us 'checkmate,' though there the path runs through Persian and Arabic rather than Latin, so the two 'mats' are likely distant strangers, not siblings.