[1] : The Collaborative International Dictionary of English v.0.48

leek \leek\ l=ek, n. as. le'ac; akin to d. look, g.
   lauch, ohg. louh, icel. laukr, sw. l"ok, dan l"og. cf.
   garlic. bot.
   a plant of the genus allium allium porrum, having
   broadly linear succulent leaves rising from a loose oblong
   cylindrical bulb. the flavor is stronger than that of the
   common onion.
   1913 webster

   wild leek, in america, a plant allium tricoccum with a
      cluster of ovoid bulbs and large oblong elliptical leaves.
      1913 webster
see also:
garlic allium allium porrum wild leek allium tricoccum 

[2] : WordNet (r) 2.0

allium porrum
     n : plant having a large slender white bulb and flat overlapping
         dark green leaves; used in cooking; believed derived from
         the wild allium ampeloprasum syn: leek, scallion
see also:
leek scallion 

Allium >> A Words
Allium, definition of term: Allium
allium_pag1.html

Allium Cepa >> A Words
Allium Cepa, definition of term: Allium Cepa
allium+cepa_pag1.html