a cappella vs classical

a cappella

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

  • Singing solely or mainly without 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. 

noun
  • A vocal performance with no instrumental accompaniment. 

classical

adj
  • Describing Western music and musicians of the late 18th and early 19th centuries. 

  • Of or pertaining to established principles in a discipline. 

  • Of or relating to the first class or rank, especially in literature or art. 

  • Describing art music (rather than pop, jazz, blues, etc), especially when played using instruments of the orchestra. 

  • Of or pertaining to the ancient Greeks and Romans, especially to Greek or Roman authors of the highest rank, or of the period when their best literature was produced; of or pertaining to places inhabited by the ancient Greeks and Romans, or rendered famous by their deeds. 

  • Pertaining to models of physical laws that do not take quantum or relativistic effects into account; Newtonian or Maxwellian. 

  • Conforming to the best authority in literature and art; chaste; pure; refined 

  • Knowledgeable or skilled in the classics; versed in the classics. 

noun
  • One that is classical in some way; for example, a classical economist. 

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