1. 
[syn: umbrella tree, umbrella magnolia, elkwood, elk-wood, Magnolia tripetala]
The Collaborative International Dictionary of English v.0.48:
Elkwood \Elk"wood`\, n.
   The soft, spongy wood of a species of Magnolia (M.
   Umbrella).
   [1913 Webster]
WordNet (r) 3.0 (2006):
elkwood
    n 1: small deciduous tree of eastern North America having creamy
         white flowers and large leaves in formations like umbrellas
         at the ends of branches [syn: umbrella tree, umbrella
         magnolia, elkwood, elk-wood, Magnolia tripetala]