"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.
early 15c., matten, "to make mats," from mat (n.1). From 1540s as "to provide with mats, to cover with mats;" meaning "to become tangled" is from 1570s. Related: Matted; matting.
"an article plaited or woven of more or less coarse natural materials (rushes, straw, twine, etc.) used as bedding, floor-coverings, etc.," Old English matte, from Late Latin matta "mat made of rushes" (4c.), probably from Punic or Phoenician matta (compare Hebrew mittah "bed, couch").
Meaning "tangled mass; anything closely set, dense, and thick" is from 1835. Meaning "thin, flat article to be placed under a dish, plate, etc. to protect the table" is by 1800. That of "piece of padded flooring used in gymnastics or wrestling" is attested from 1892; hence figurative phrase go to the mat "do battle" (1910). The Latin word also is the source of German Matte, matze; Dutch mat, Italian matta. French natte "mat, matting" is from Late Latin secondary form natta (compare napkin).
"tangled and lying flat" (of hair, vegetation, fibers, etc.), 1610s, past-participle adjective from mat (v.).
"process of making mats," 1720, from mat (n.1). Meaning "fabric of coarse material for mats" is from 1748.