c.1400, from O.Fr. mosaicq "mosaic work," from M.L. musaicum "mosaic work, work of the Muses," neut. of musaicus "of the Muses," from L. Musa (see muse). Medieval mosaics were often dedicated to the Muses. The word formed in M.L. as though from Gk., but the (late) Gk. word for "mosaic work" was mouseion. Figurative use is from 1640s. Related: Mosaicist.