NARTHEX Meaning of NARTHEX in English [nar.thex] n [LGk narthex, fr. Gk, giant fennel, cane, casket] (ca. 1673) 1: the portico of an ancient church 2: a vestibule leading to the nave of a church Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012