descant vs motet

descant

noun
  • A counterpoint melody sung or played above the theme. 

  • A lengthy discourse on a subject. 

verb
  • To sing or play a descant. 

  • To discuss at length. 

motet

noun
  • A composition adapted to sacred words in the elaborate polyphonic church style; an anthem. 

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