a cappella vs solitary

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. 

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. 

noun
  • A vocal performance with no instrumental accompaniment. 

solitary

adj
  • Performed, passed, or endured alone 

  • Living or being by oneself; alone; having no companion present 

  • Not much visited or frequented; remote from society 

  • Single; individual; sole. 

  • gloomy; dismal, because of not being inhabited. 

  • Not inhabited or occupied; without signs of inhabitants or occupation; desolate; deserted 

  • Not associated with others of the same kind. 

noun
  • One who lives alone, or in solitude; an anchorite, hermit or recluse. 

  • Solitary confinement. 

  • The state of being solitary; solitude 

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