Homozygous dominant: Two dominant alleles (AA)
Homozygous recessive: Two recessive alleles (aa)
Heterozygous: One dominant and one recessive (Aa)
Incomplete dominance: Heterozygotes who show a blend of the dominant and recessive trait. Example in flowers, where if the dominant color is purple and the recessive color is white, the heterozygous flower will come out pink.
Codominance: The presence of both the dominant and recessive traits, such as in siamese cats.