The Collaborative International Dictionary of English v.0.48:

Karyokinesis \Kar"y*o*ki*ne`sis\
   (k[a^]r`[i^]*[-o]*k[-i]*n[=e]"s[i^]s), n. [NL., fr. Gr.
   ka`ryon a nut, kernel + kinei^n to move.]
   1. (Biol.) The indirect division of cells in which, prior to
      division of the cell protoplasm, complicated changes take
      place in the nucleus, attended with movement of the
      nuclear fibrils; -- opposed to karyostenosis. The
      nucleus becomes enlarged and convoluted, and finally the
      threads are separated into two groups which ultimately
      become disconnected and constitute the daughter nuclei.
      Called also mitosis. See Cell development, under
      Cell.
      [1913 Webster]

   2. The changes that occur in the nucleus of a cell,
      especially movements of the chromosomes, in the process of
      cell division.
      [PJC]

WordNet (r) 3.0 (2006):

karyokinesis
    n 1: organic process consisting of the division of the nucleus
         of a cell during mitosis or meiosis