A tall umbelliferous plant (Ferula communis). See Giant fennel, under Fennel. [1913 Webster]
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. [1913 Webster]
narthex, n.
1 a railed-off antechamber or porch etc. at the western entrance of some early Christian churches, used by catechumens, penitents, etc.
2 a similar antechamber in a modern church.
Etymology
L f. Gk narthex giant fennel, stick, casket, narthex