Definition of: influenza

(in′fl·en′zə) noun
1. Pathol. A contagious, infective, sometimes epidemic disease generally caused by a filtrable virus and commonly characterized by inflammation of the upper air passages, attended by fever and nervous and muscular prostration.
2. A contagious disease common among horses: characterized by its attack upon the mucous membranes of the throat and eyelids. [<Ital. <influire influence <L influere flow in. Doublet of INFLUENCE.]
—in′flu·en′zal adjective
—in′flu·en′za·like′ adjective