Rus vs Russia

Rus

name
  • The nation of Russia, especially in a transcendent or romantic sense referring to the history and culture of the country. 

  • The medieval East Slavic state established by these same warrior merchants in the 9th century, whose capital was first in Novgorod and then in Kiev; Kievan Rus. 

  • A people made up of Scandinavian warrior merchants who travelled Eastern European river-roads from the eighth century, and whose settlements around Novgorod, Kiev and the Volga and Dnieper gave rise to the Russian principalities. 

  • Any of the medieval East Slavic principalities ruled by this class, especially Kievan Rus. 

noun
  • A person from Rus. 

Russia

name
  • The Russian Empire; the tsarist empire in Russia lasting from 1721 to 1917. 

  • The Union of Soviet Socialist Republics (a very common name, although more formally Russia, the RSFSR, was one of several constituent republics of the USSR). 

  • A country in Eastern Europe and North Asia, bordering on the Pacific and Arctic Oceans and the Baltic, Black, and Caspian Seas; established as an independent country in 1991 upon the dissolution of the Soviet Union, it is the largest country in the world. Co-official name: Russian Federation, formerly the Russian Soviet Federative Socialist Republic (RSFSR) (among other names) from 1917 to 1991. Capital and largest city: Moscow. 

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