means A picture or pattern made by fitting together many small pieces of colored stone, glass, or tile, or, by extension, anything composed of varied parts forming a whole.

from From Medieval Latin musaicum, work belonging to the Muses — the same nine goddesses who gave us 'museum,' a place sacred to them. The thread runs through Greek mouseios, 'of the Muses,' and into Italian mosaico before reaching English. So every tiled floor quietly claims kinship with poetry and music: art assembled, fragment by fragment, under divine patronage.