a cappella vs twitter

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. 

twitter

noun
  • A tremulous broken sound. 

  • The sound of a succession of chirps as uttered by birds. 

  • Unwanted flicker that occurs in interlaced displays when the image contains vertical detail that approaches the horizontal resolution of the video format. 

  • A slight trembling of the nerves. 

verb
  • To make the sound of a half-suppressed laugh; to titter; to giggle. 

  • To have a slight trembling of the nerves; to be excited or agitated. 

  • To utter a succession of chirps. 

  • (of a person) To talk in an excited or nervous manner. 

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