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

jonquil \jon"quil\, jonquille \jon"quille\, n. f. jonquille,
   fr. l. juncus a rush, because it has rushlike leaves. bot.
   a bulbous plant of the genus narcissus narcissus
   jonquilla, allied to the daffodil. it has long, rushlike
   leaves, and yellow or white fragrant flowers. the root has
   emetic properties. it is sometimes called the rush-leaved
   daffodil. see illust. of corona.
   1913 webster
see also:
narcissus narcissus jonquilla rush-leaved daffodil corona 

[2] : WordNet (r) 2.0

jonquil
     n 1: widely cultivated ornamental plant native to southern europe
          but naturalized elsewhere having fragrant yellow or
          white clustered flowers syn: narcissus jonquilla
     2: often used colloquially for any yellow daffodil
see also:
narcissus jonquilla 

Jonquil >> J Words
Jonquil, definition of term: Jonquil
jonquil_pag1.html