amitosis

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Direct cell division by simple cleavage of the nucleus, without spindle formation or the appearance of chromosomes.

from The Century Dictionary.

• noun In cytology, direct celldivision, akinesis or karyostenosis, as opposed to the indirect form of division (mitosis, karyokinesis, which see): so called from the absence of thread-like figures in the nucleus.

from the GNU version of the Collaborative International Dictionary of English.

• noun (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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun biology Direct division of a cell by cleavage of the nucleus without the formation of chromosomes

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the direct method of cell division characterized by simple division of the nucleus without formation of chromosomes