a cappella vs scream

a cappella

noun
  • A vocal performance with no instrumental accompaniment. 

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. 

scream

noun
  • A form of singing associated with the metal and screamo styles of music. It is a loud, rough, distorted version of the voice; rather than the normal voice of the singer. 

  • A loud, emphatic, exclamation of extreme emotion, especially horror, fear, excitement, or anger; it may comprise a word or a sustained, high-pitched vowel sound. 

  • Used as an intensifier. 

  • A loud vocalisation of many animals, especially in response to pain or fear. 

  • An exclamation mark. 

verb
  • To cry out with a shrill voice; to utter a sudden, shout outcry, or shrill, loud cry, as in fright or extreme pain; to screech, to shriek. 

  • To move quickly; to race. 

  • To be very indicative of; clearly having the characteristics of. 

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