Codominance is a genetic phenomenon where two different alleles are expressed equally in the phenotype of an organism. This means that both traits appear together without one overshadowing the other. For example, in blood type, individuals with one allele for type A and another for type B will have type AB blood, showing both traits simultaneously. In codominance, neither allele is recessive, allowing for a blend of characteristics. A classic example is seen in flower color in certain plants, where a cross between red and white flowers can produce offspring with both red and white patches, rather than a mix of colors.