(1) A division or separation of form.
(3) (embryology) The repeated division of a fertilized ovum, producing a cluster of cells with the same size as the original zygote. . (4) (chemistry) The splitting of a large or complex molecule into smaller or simpler molecules.
In embryology, cleavage is the first stage of embryogenesis. It pertains to the repeated mitotic division of a zygote into blastomeres that cluster to a compact mass called morula. Cleavage continues until blastula is formed. The various types of cleavage are: