hymn vs psalmody

hymn

verb
  • To praise or extol in hymns. 

  • To sing a hymn. 

noun
  • A song of praise or worship, especially a religious one. 

psalmody

verb
  • To celebrate in psalms. 

noun
  • A collection of psalms. 

  • The singing or the writing of psalms. 

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