bai vs postilion

bai

noun
  • A people of the Yunnan province of China. 

  • A marshy meadow in sub-Saharan Africa. 

postilion

noun
  • A rider mounted on the near (left) leading horse who guides the team pulling a carriage. 

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