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

onion \on"ion\, n. f. ognon, fr. l. unio oneness, unity, a
   single large pearl, an onion. see one, union.
   1. bot. a liliaceous plant of the genus allium allium
      cepa, having a strong-flavored bulb and long hollow
      leaves; also, its bulbous root, much used as an article of
      food. the name is often extended to other species of the
      genus.
      1913 webster

   2. the flavor of an onion1.
      pjc

   onion fish zool., the grenadier.

   onion fly zool. a dipterous insect whose larva feeds upon
      the onion; especially, anthomyia ceparum and ortalis
      flexa.

   welsh onion. bot. see cibol.

   wild onion bot., a name given to several species of the
      genus allium.
      1913 webster
see also:
one union allium allium cepa onion fish onion fly 
anthomyia ceparum ortalis flexa welsh onion cibol wild onion 

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

welsh \welsh\, a. as. waelisc, welisc, from wealh a stranger,
   foreigner, not of saxon origin, a welshman, a celt, gael;
   akin to ohg. walh, whence g. waumlsch or welsch, celtic,
   welsh, italian, french, foreign, strange, ohg. walhisc; from
   the name of a celtic tribe. see walnut.
   of or pertaining to wales, or its inhabitants. sometimes
   written also welch.
   1913 webster

   welsh flannel, a fine kind of flannel made from the fleece
      of the flocks of the welsh mountains, and largely
      manufactured by hand.

   welsh glaive, or welsh hook, a weapon of war used in
      former times by the welsh, commonly regarded as a kind of
      poleax. --fairholt. --craig.

   welsh mortgage o. eng. law, a species of mortgage, being
      a conveyance of an estate, redeemable at any time on
      payment of the principal, with an understanding that the
      profits in the mean time shall be received by the
      mortgagee without account, in satisfaction of interest.
      --burrill.

   welsh mutton, a choice and delicate kind of mutton obtained
      from a breed of small sheep in wales.

   welsh onion bot., a kind of onion allium fistulosum
      having hollow inflated stalks and leaves, but scarcely any
      bulb, a native of siberia. it is said to have been
      introduced from germany, and is supposed to have derived
      its name from the german term waumlsch foreign.

   welsh parsley, hemp, or halters made from hemp. obs. 
      jocular --j. fletcher.

   welsh rabbit. see under rabbit.
      1913 webster
see also:
walnut welch welsh flannel welsh glaive welsh hook welsh mortgage 
welsh mutton welsh onion allium fistulosum welsh parsley welsh rabbit 
rabbit 

[3] : WordNet (r) 2.0

welsh onion
     n : asiatic onion with slender bulbs; used as early green onions
         syn: japanese leek, allium fistulosum
see also:
japanese leek allium fistulosum 

Onion >> O Words
Onion, definition of term: Onion
onion_pag1.html

Welsh >> W Words
Welsh, definition of term: Welsh
welsh_pag1.html

Onion Salt >> O Words
Onion Salt, definition of term: Onion Salt
onion+salt_pag1.html

Wild Onion >> W Words
Wild Onion, definition of term: Wild Onion
wild+onion_pag1.html

Green Onion >> G Words
Green Onion, definition of term: Green Onion
green+onion_pag1.html