(1) A pattern consisting of numerous small pieces (or elements) fitted together.
In genetics, a mosaic or mosaicism refers to the presence of two (or more) populations of cells, each with different genotypes in an individual. It may be a gonadal mosaicism or tissue mosaicism. An example of mosaicism is 46/47 XY/XXY mosaic.
Word origin: Middle English musycke, from Old French mosaique, from Old Italian mosaico, from Medieval Latin mūsāicum, neuter of mūsāicus, of the Muses, from Latin Mūsa, Muse, from Greek Mousa.