Or″pi‐ment (?), n. [F., fr. L. auripigmentum; aurum gold + pigmentum pigment. Cf. Aureate, Pigment, Orpin, Orpine.] (Chem.) Arsenic sesquisulphide, produced artificially as an amorphous lemon-yellow powder, and occurring naturally as a yellow crystalline mineral; — formerly called auripigment. It is used in king's yellow, in white Indian fire, and in certain technical processes, as indigo printing.
Our orpiment and sublimed mercurie. Chaucer.
Red orpiment, realgar; the red sulphide of arsenic. — Yellow orpiment, king's yellow.