What is the meaning of Matte?

A partly reduced copper sulphide, obtained by alternately roasting and melting copper ore in separating the metal from associated iron ores, and called coarse metal, fine metal, etc., according to the grade of fineness. On the exterior it is dark brown or black, but on a fresh surface is yellow or bronzy in color.

Source: Webster’s Revised Unabridged Dictionary (1913), via OPTED