Influenzavirus In·flu·en·za·vi·rus (ĭn'fl&oomacr;-ěn'zə-vī'rəs)
n.
A genus of the Orthomyxoviridae family, including the viruses that cause influenza A and B; each type has a stable nucleoprotein group antigen common to all strains of the type, but distinct from that of the other type.