Two copies of an allele. Will always pass on one copy of said allele when breeding. A super pastel is a homozygous pastel and all of its offspring will carry pastel. Homozygous also refers to the visual version of a recessive gene (as it takes two copies to make a recessive gene visual). Ex: a piebald is homozygous and will always pass on one copy of its genetics when bred (so pied to normal = all het pied babies).