â¢ TORNADO (noun). The noun TORNADO has 2 senses: 1. a localized and violently destructive windstorm occurring over land characterized by a funnel-shaped cloud extending toward the ground. 2. a purified and potent form of cocaine that is smoked rather than snorted. Familiarity information: TORNADO used as a noun is rare.
In other words, nothing is different about the way these alleles are inherited; the only difference is in the way the alleles determine phenotype when they are combined. As opposed to partial dominance, codominance occurs when the phenotypes of both parents are simultaneously expressed in the same offspring organism.
A typical example showing codominance is the ABO blood group system. For instance, a person having A allele and B allele will have a blood type AB because both the A and B alleles are codominant with each other. Codominance is different from incomplete dominance in a way that the former has both alleles manifesting the phenotypes whereas the latter produces an intermediate phenotype.