niello

noun pl. nielli -·li (-ē) or niellos -·los

1. any of a number of alloys of sulfur with silver, lead, copper, etc., characterized by a deep-black color and used to decorate metallic objects by means of inlay
2. the process of decorating with niello
3. something decorated in this way

Etymology: It < VL *nigellum < L nigellus, somewhat black, dark < niger, black

transitive verb nielloed -·loed, nielloing -·lo·ing