Nĭ-ĕl'lo, n.

n. [It. niello, Sp. & Pr. niel, Fr. nielle, O. Fr. neel, L. Lat. nigellum, a black or blackish enamel, from Lat. nigellus, diminutive of niger, black.] A style of ornamentation applied to metal before the invention of engraving. The process consisted in drawing upon gold, silver, &c., a design, which was then cut out with a pointed instrument, and on the plate thus prepared, a black composition of copper, gold, silver, and lead, heated together, was laid, and, by heat, was made to flow into the lines of the design. The metal was then scraped and burnished, and presented the effect of a drawing in black upon gold or silver.