"porch at the west end of early churches" (used by penitents not admitted to the body of the church), 1670s, from Late Greek narthex, in classical Greek "giant fennel," of unknown origin. The architectural feature allegedly so called from fancied resemblance of porch to a hollow stem. The word also was used in Greek to mean "a small case for unguents, etc." According to Hesiod ("Theogeny"), Prometheus conveyed fire from Heaven to Earth in hollow fennel stalks. Related: Narthecal.