Old English fenol, finul, finol "fennel," perhaps via (or influenced by) Old French fenoil (13c.) or directly from Vulgar Latin *fenuculum, from Latin feniculum/faeniculum, diminutive of fenum/faenum "hay," probably literally "produce" (see fecund). Apparently so called from the hay-like appearance of its feathery green leaves and its sweet odor.
*dhē(i)-, Proto-Indo-European root meaning "to suck."
It forms all or part of: affiliate; affiliation; effeminate; effete; epithelium; fawn (n.) "young deer;" fecund; fellatio; Felicia; felicitate; felicity; Felix; female; feminine; femme; fennel; fenugreek; fetal; feticide; fetus; filial; filiation; filicide; filioque; fitz; infelicity.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit dhayati "sucks," dhayah "nourishing;" Greek thēlē "mother's breast, nipple," thēlys "female, fruitful;" Latin felare "to suck," femina "woman" ("she who suckles"), felix "happy, auspicious, fruitful," fetus "offspring, pregnancy;" fecundus "fruitful, fertile, productive; rich, abundant;" Old Church Slavonic dojiti "to suckle," dojilica "nurse," deti "child;" Lithuanian dėlė "leech;" Old Prussian dadan "milk;" Gothic daddjan "to suckle;" Old Swedish dia "suckle;" Old High German tila "female breast;" Old Irish denaim "I suck," dinu "lamb."
"fennel-like umbelliferous plant of the carrot family found wild in Egypt and Syria and cultivated for its fruit," Old English cymen, from Latin cuminum, from Greek kyminon, cognate with Hebrew kammon, Arabic kammun. Related: Cumic.
"porch at the west end of early churches," the end furthest from the sanctuary (used by penitents not admitted to the body of the church), 1670s, from Late Greek narthex, in classical Greek "giant fennel," a word of unknown origin, perhaps Pre-Greek. The architectural feature allegedly was so called from the fancied resemblance of the 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.
"long, narrow ulcer," late 14c., from Latin fistula "a pipe; ulcer," which is of uncertain origin. Related: Fistular; fistulous (Latin fistulosus "full of holes; tubular").
No certain etymology. The best comparison seems to be with festuca "stalk, straw" and maybe ferula "giant fennel" (if from *fesula): the forms of a "pipe" and a "stalk" are similar. The vacillation between fest- and fist- occurs within festuca itself, and might be dialectal, or allophonic within Latin. [de Vaan]
1896, marathon race, from story of Greek hero Pheidippides, who in 490 B.C.E. ran to Athens from the Plains of Marathon to tell of the allied Greek victory there over Persian army. The original story (Herodotus) is that he ran from Athens to Sparta to seek aid, which arrived too late to participate in the battle.
It was introduced as an athletic event in the 1896 revival of the Olympic Games, based on a later, less likely story, that Pheidippides ran to Athens from the battlefield with news of the victory. The word quickly was extended to mean "any very long event or activity." The place name is literally "fennel-field." Related: Marathoner (by 1912); Marathonian.