1765, "an alloy of copper, zinc, and tin resembling gold," from French or moulu, literally "ground gold," from or "gold" (from Latin aurum, from PIE *aus- (2) "gold;" see aureate) + moulu "ground up," past participle of moudre "to grind," from Latin molere "to grind" (from PIE root *mele- "to crush, grind"). The sense of the word before it reached English began as "gold leaf prepared for gilding bronze, brass, etc.," then shifted to "gilded bronze," then to various prepared metallic substances resembling it.
