matte (n.1)

"sheet of backing material," 1845, from French mat "dull surface or finish" (15c.), noun use of Old French mat (adj.) "dull, beaten down," for which see mat (adj.). The word has been confused with mat (n.1), especially as the latter was used late 19c. for "piece of thick paper or other material placed for ornament or protection immediately under the glass of a picture-frame, with the central part cut out, for the proper display of the picture." As a verb, "to mount (a print) on a cardboard backing," by 1965. Related: Matted; matting.