\Am`i*to"sis\, n. [NL. See {A-} not, and {Mitosis}.]
(Biol.)
Cell division in which there is first a simple cleavage of
the nucleus without change in its structure (such as the
formation of chromosomes), followed by the division of the
cytoplasm; direct cell division; -- opposed to {mitosis}. It
is not the usual mode of division, and is believed by many to
occur chiefly in highly specialized cells which are incapable
of long-continued multiplication, in transitory structures,
and in those in early stages of degeneration.