a cappella vs rhapsody

a cappella

noun
  • A vocal performance with no instrumental accompaniment. 

adv
  • In a manner of a choir with no instrumental accompaniment; literally, "in the style of the (Sistine) Chapel (in Rome)", such as a musical Mass done a cappella. 

adj
  • Singing solely or mainly without instrumental accompaniment. 

  • Related to a form of purely vocal music mostly associated with American college performance groups. 

rhapsody

noun
  • An instrumental composition of irregular form, often incorporating improvisation. 

  • An exaggeratedly enthusiastic or exalted expression of feeling in speech or writing. 

  • An epic poem, or part of one, suitable for uninterrupted recitation. 

verb
  • Followed by about, on, over, or upon: to speak with exaggerated or rapturous enthusiasm. 

  • To say (something) with exaggerated or rapturous enthusiasm. 

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