Song vs Yuan

Song

name
  • A former dynasty in China, reigning from the end of the Five Dynasties and Ten Kingdoms to the beginning of the Yuan. 

  • A surname from Khmer. 

  • A former empire in China, occupying the eastern half of modern China. 

  • A surname from Chinese. 

  • A local government area of Adamawa State, Nigeria. 

  • A river in Papua New Guinea 

  • The era of Chinese history during which the dynasty reigned. 

  • A river in China; any of various minor rivers in China. 

Yuan

name
  • The imperial dynasty of China from 1279 to 1368. 

  • A surname from Chinese. 

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