NATURAL RESINS — Organic compounds of different nature and structure, of vegetal or animal origin.
NEUTRAL CLEANER — A water-soluble substance with a neutral pH used to clean delicate tiles or mosaics. Floors have to be rinsed with water after use.
NIBBLING — The process of forming a tile edge by cutting of, or "nibbling" away, small fragments with the tile nippers.
Nucleus — In Roman mosaic, upper layer of mortar in the bedding for a mosaic pavement.
