Hibiscus \Hi*bis"cus\, n. [L., marsh mallow; cf. Gr. ?.] (Bot.) A genus of plants (herbs, shrubs, or trees), some species of which have large, showy flowers. Some species are cultivated in India for their fiber, which is used as a substitute for hemp. See {Althea}, {Hollyhock}, and {Manoe}. [1913 Webster]