Source : Webster's Revised Unabridged Dictionary (1913)

Greenhouse \Green"house`\, n.
   A house in which tender plants are cultivated and sheltered
   from the weather.

Source : WordNet®

greenhouse
     adj : of or relating to or caused by the greenhouse effect;
           "greehouse gases"

greenhouse
     n : a building with glass walls and roof; for the cultivation
         and exhibition of plants under controlled conditions
         [syn: {nursery}, {glasshouse}]