The Collaborative International Dictionary of English v.0.48:

Ulmus \Ul"mus\, n. [L., an elm.] (Bot.)
   A genus of trees including the elm.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Ulmus
    n 1: type genus of family Ulmaceae; deciduous trees having
         simple serrate leaves; widely distributed in temperate
         regions [syn: Ulmus, genus Ulmus]