private conversation vs tête-à-tête

private conversation

tête-à-tête

adv
  • In private, between two people; head-to-head. 

noun
  • A bench or sofa that allows two people to talk face-to-face, especially one that is S-shaped. 

  • A face-to-face meeting, or private conversation between two people, usually in an intimate setting; a head-to-head. 

  • A variety of early flowering, fragrant daffodil. 

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