Enamel, "Vitrifiable substance composed of silicious sand to which oxides are added to give a very wide range of colours suitable for the decoration of metallic surfaces, especially gold, silver or copper. When fired, enamel adheres to the metal and acquires the consistency of glass." (Berner)
Champlever, "Describes a metal surface that has been hollowed using a graver to form cells that will be filled with enamel." (FHH)
Cloisonné, "An enamelling technique in which the outline of the subject is formed by thin flat metal wires set on the surface to be enamelled to form cells. These cells are filled with enamel and fired. After polishing, the wires bring out the subject or pattern that is set in the enamel. Cloisonné is used to describe both the technique and the end result." (FHH)