The Collaborative International Dictionary of English v.0.48:

Fraxinus \Frax"i*nus\, prop. n. [L., the ash tree.] (Bot.)
   A genus of deciduous forest trees, found in the north
   temperate zone, and including the true ash trees.
   [1913 Webster]

   Note: Fraxinus excelsior is the European ash; Fraxinus
         Americana, the white ash; Fraxinus sambucifolia, the
         black ash or water ash.
         [1913 Webster]

WordNet (r) 3.0 (2006):

Fraxinus
    n 1: ash [syn: Fraxinus, genus Fraxinus]