Wordnet 3.0
NOUN (1)
1. 
 a mountain in the Alps on the border between Switzerland and Italy (14,780 feet high); 
 noted for its distinctive shape; 
The Collaborative International Dictionary of English v.0.48:
Matterhorn \Matterhorn\ prop. n.
   A mountain in Italy and Switzerland, 14,690 feet high.
   Note: According to WordNet, 14,780 feet high
         [WordNet 1.5]
WordNet (r) 3.0 (2006):
Matterhorn
    n 1: a mountain in the Alps on the border between Switzerland
         and Italy (14,780 feet high); noted for its distinctive
         shape