grassroots vs mainstream

grassroots

adj
  • Of, or relating to people or society at the local level, particularly in politics, social movements, etc.; of the grass roots. 

mainstream

adj
  • Used or accepted broadly rather than by small portions of a population or market. 

noun
  • That which is common; the norm. 

  • The principal current in a flow, such as a river or flow of air 

verb
  • To become mainstream. 

  • To popularize, to normalize, to render mainstream. 

  • To educate (a disabled student) together with non-disabled students. 

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