look up any word, like sex:
 
1.
literally means ("not coming apart") when, sometimes in meiosis, homologous chromosomes or sister chromatids that are paired up together during metaphase remain stuck together instead of separating. Simply stated, nondisjunction is the failure of chromosomes to correctly separate during either meiosis I or II. Also, nondisjunction leads to aneuploidy.
It seems that these chromosomes did not separate correctly during metaphase, which I conclude that they went through nondisjunction.
by T2o8 March 21, 2010