mixing vs pairing

mixing

noun
  • The act, or the result of making a mixture. 

adj
  • Of a stochastic process, to be asymptotically independent (in a precise mathematical sense). 

pairing

noun
  • The combination or union of two things. 

  • An agreement between two members of a legislative body holding opposite opinions to refrain from voting, so that both may absent themselves. 

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