zygosity /(zī̇*gŏs"ĭ*ty̆)/

zy·gos·i·ty

zygosity

n.
  1. The property of being either homogeneous or heterogeneous with respect to the allelic genes determining some hereditary trait in a diploid or polyploid organism; if homogeneous, the organism is homozygous; if heterogeneous, it is heterozygous. (Biol.)