mainstay vs sponsor

mainstay

noun
  • Someone or something that can be depended on to make a regular contribution. 

  • A stabilising rope from the top of the mainmast to the bottom of the foremast. 

  • A chief support. 

sponsor

noun
  • A person or organisation with some sort of responsibility for another person or organisation, especially where the responsibility has a religious, legal, or financial aspect. 

  • One that pays all or part of the cost of an event, a publication, or a media program, usually in exchange for advertising time. 

  • A senior member of a twelve step or similar program assigned to a guide a new initiate and form a partnership with him. 

verb
  • To be a sponsor for. 

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