a cappella vs rock and roll

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. 

rock and roll

noun
  • A style of vigorous dancing associated with this genre of music. 

  • An intangible feeling, philosophy, belief or allegiance relating to rock music, characterized by unbridled enthusiasm, hedonism, and cynical regard for authoritarian bodies. 

  • Dole, payment by the state to the unemployed. 

  • The full automatic fire capability selection on a selective fire weapon. 

  • The ability to run the picture and audio back and forth in synchronization, allowing the correction of mistakes during dubbing. 

  • A genre of popular music that evolved in the 1950s from a combination of rhythm and blues and country music, characterized by electric guitars, strong rhythms, and youth-oriented lyrics. 

verb
  • To play rock and roll music. 

  • To start, commence, begin, get moving. 

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