Wordnet 3.0
NOUN (2)
1. 
 a native or inhabitant of Brittany (especially one who speaks the Breton language); 
2. 
 a Celtic language of Brittany; 
The Collaborative International Dictionary of English v.0.48:
Breton \Bret"on\, a. [F. breton.]
   Of or relating to Brittany, or Bretagne, in France. -- n. A
   native or inhabitant of Brittany, or Bretagne, in France;
   also, the ancient language of Brittany; Armorican.
   [1913 Webster]
WordNet (r) 3.0 (2006):
Breton
    n 1: a native or inhabitant of Brittany (especially one who
         speaks the Breton language)
    2: a Celtic language of Brittany