antiphony vs back answer

antiphony

noun
  • alternate, or responsive ideas or opinions; juxtaposition 

  • alternate, or responsive singing by a choir split into two parts; a piece sung or chanted in this manner 

back answer

noun
  • A sharp reply given to someone. 

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