burghmaster vs viceroy

burghmaster

noun
  • A burgomaster. 

  • An officer who directs and lays out the meres or boundaries for the workers. 

viceroy

noun
  • A zongdu. 

  • An orange and black North American butterfly (Limenitis archippus), so named because it is similar to, but smaller than, the monarch butterfly. 

  • One who governs a country, province, or colony as the representative of a monarch. 

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