locus vs region

locus

noun
  • A place or locality, especially a centre of activity or the scene of a crime. 

  • A fixed position on a chromosome that may be occupied by one or more genes. 

  • The set of all points whose coordinates satisfy a given equation or condition. 

  • A passage in writing, especially in a collection of ancient sacred writings arranged according to a theme. 

region

noun
  • A place in or a part of the body in any way indicated. 

  • Any considerable and connected part of a space or surface; specifically, a tract of land or sea of considerable but indefinite extent; a country; a district; in a broad sense, a place without special reference to location or extent but viewed as an entity for geographical, social or cultural reasons. 

  • A subnational region of Chile; equivalent to province. 

  • An administrative subdivision of the European Union. 

  • A subprovincial region of Quebec; the primary level subdivision; a prefecture. 

  • The inhabitants of a region or district of a country. 

  • Such a division of the city of Rome and of the territory about Rome, of which the number varied at different times; a district, quarter, or ward. 

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