From BiblePortal Wikipedia

Webster's Dictionary [1]

(1): ( a.) Of or pertaining to the style of work called mosaic; formed by uniting pieces of different colors; variegated; tessellated; also, composed of various materials or ingredients.

(2): ( n.) A picture or design made in mosaic; an article decorated in mosaic.

(3): ( n.) A surface decoration made by inlaying in patterns small pieces of variously colored glass, stone, or other material; - called also mosaic work.

(4): ( a.) Of or pertaining to Moses, the leader of the Israelites, or established through his agency; as, the Mosaic law, rites, or institutions.

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [2]

(Lat. Musicum), ornamental work formed by inlaying small pieces, usually cubes, of glass, stone, etc. It was much used by the Romans in floors and on the walls of houses, and many specimens which have been discovered are rendered exceedingly beautiful by the introduction of different-colored materials, and are made to represent a variety of subjects with figures and animals; others are of coarser execution, and exhibit only such patterns as frets, guilloches, foliage, etc.

In the Middle Ages this kind of work continued to be used in Italy and some other parts of the Continent, and was applied to walls and vaults of churches; in England it was never extensively employed, though used in some parts of the shrine of Edward the Confessor, on the tomb of Henry III, and in the paving of the choir at Westminster Abbey, and Becket's crown at Canterbury, where curious patterns may be seen. Mosaic-work is still executed with great skill by the Italians.