madrigal vs motet

madrigal

noun
  • A polyphonic song for about six voices, from 16th century Italy. 

  • A song for a small number of unaccompanied voices; from 13th century Italy. 

  • A short poem, often pastoral, and suitable to be set to music. 

motet

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

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