or·tho·myx·o·vi·rus 
(ôr′thō-mĭksə-vī′rəs)
(ôr′thō-mĭksə-vī′rəs)n. pl. or·tho·myx·o·vi·rus·es
Any of a family of single-stranded RNA viruses, including the virus that causes influenza.
[ORTHO-, correct (from the fact that the viruses cause influenza, in contrast to the paramyxoviruses causing parainfluenza ) + MYXOVIRUS.]