The process of decorating by inserting shaped pieces of a material (not enamel or niello) into the surface or ground of an object so that the surfaces of both are level.
Articles of jewelry have been inlaid by insetting into metal thin pieces of gemstones or of metal or other material. This is distinct from the various methods of decorating with enamelling into the surface, e.g. cloisonné, champlevé, pliqué à jour, and basse taille, and also from niello.
Other styles of inlaying in metal can be executed by several methods: by inserting thin strips of gold, silver or other metal into narrow grooves in a metal surface, e.g. damascened ware; by cutting a pattern into a sheet of metal which is then soldered to another metal sheet and filling in the spaces with thin pieces of a soft decorative metal, e.g. ivory or tortoise shell or with thin slices of gemstones cemented into place; by making a recess in a piece of metal by chiselling or etching, and then filling it in with another hard material that is not enamel.
From: An Illustrated Dictionary of Jewelry, autor: Harold Newman, publishers: Thames and Hudson