The Collaborative International Dictionary of English v.0.48:

hardwood \hard"wood`\ adj.
   Made of the hard-to-cut wood of a broad-leaved tree, as e.g.
   oak; consisting of a hardwood; as, hardwood floors; -- of
   wood and wooden objects.
   [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

hardwood \hard"wood`\ n.
   The wood of broad-leaved dicotyledonous trees (as
   distinguished from the wood of conifers); also items made
   from such wood; as, decorative hardwood.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

hardwood
    n 1: the wood of broad-leaved dicotyledonous trees (as
         distinguished from the wood of conifers)