a cappella vs individual

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. 

individual

adj
  • Intended for a single person as opposed to more than one person. 

  • Not divisible without losing its identity. 

  • Relating to a single person or thing as opposed to more than one. 

noun
  • An object, be it a thing or an agent, as contrasted to a class. 

  • A person considered alone, rather than as belonging to a group of people. 

  • An element belonging to a population. 

  • A single physical human being as a legal subject, as opposed to a legal person such as a corporation. 

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