Breton vs Briton

Breton

noun
  • The Celtic language of Brittany. 

  • A person from Brittany. 

adj
  • Of or pertaining to Brittany. 

name
  • A village in Alberta, Canada. 

Briton

noun
  • An inhabitant of Great Britain, particularly (historical) a Celt from the area of Roman Britain or (obsolete) a Welshman. 

  • A citizen of the United Kingdom or (historical, obsolete) its overseas empire. 

How often have the words Breton and Briton occurred in a corpus of books? (source: Google Ngram Viewer )