n. A design in black on a surface of silver, as that of a plaque, chalice, or any ornamental or useful object, formed by engraving the design and then filling up the incised furrows with an alloy composed of silver, copper, lead, crude sulphur, and borax, thus producing the effect of a black drawing on the bright surface. The process is of Italian origin, and is still extensively practised in Russia, where the finest niello is now produced. In many examples, conversely, the ground is cut out and inlaid with the black alloy, on which the design appears white or bright, as in the cut.n. An impression taken from the engraved surface before the incised lines have been filled up.n. The dark compound used for such inlays in silver, made up of different alloys of sulphur, silver, copper, etc.n. Inlaid work of the kind defined above.To decorate by means of niello-work; treat with niello or by the niello process.