I. nē-ˈe-(ˌ)lō noun
( plural ni·el·li -(ˌ)lē ; or niellos )
Etymology: Italian, from Medieval Latin nigellum, from neuter of Latin nigellus blackish, diminutive of niger black
Date: 1816
1. : any of several black enamel-like alloys usually of sulfur with silver, copper, and lead
2. : the art or process of decorating metal with incised designs filled with niello
3. : a piece of metal or an object decorated with niello
II. transitive verb
Date: 1866
: to inlay or ornament with niello