Mosaic pieces are small pieces of stone, glass, ceramic, or other material used to create a larger image or pattern. INLAY is a five-letter term for a mosaic piece that is set into a surface. TESSERA is a seven-letter term for a small cube-shaped mosaic piece. TILE is a four-letter term for a flat, thin mosaic piece. Smalto is a six-letter term for a mosaic piece made of enameled glass. All of these terms refer to the individual pieces used to create a mosaic.