‖Nar″thex (?), n. [L., giant fennel, Gr. νάρθηξ.] 1. (Bot.) A tall umbelliferous plant (Ferula communis). See Giant fennel, under Fennel.
2. (Arch.) The portico in front of ancient churches; sometimes, the atrium or outer court surrounded by ambulatories; — used, generally, for any vestibule, lobby, or outer porch, leading to the nave of a church.