conversation vs head-to-head

conversation

verb
  • To engage in conversation (with). 

noun
  • Expression and exchange of individual ideas through talking with other people; also, a set instance or occasion of such talking. 

  • The protocol-based interaction between systems processing a transaction. 

  • The back-and-forth play of the blades in a bout. 

head-to-head

adv
  • Directly, one-to-one. 

  • Facing one another. 

adj
  • Direct, one-to-one. 

How often have the words conversation and head-to-head occurred in a corpus of books? (source: Google Ngram Viewer )