bagpipes vs coo

bagpipes

noun
  • A musical wind instrument of Celtic origin, possessing a flexible bag inflated by bellows, a double-reed melody pipe and up to four drone pipes; any aerophone that produces sound using air from a reservoir to vibrate enclosed reeds. 

coo

noun
  • The murmuring sound made by a dove or pigeon. 

  • An expression of pleasure made by a person. 

verb
  • To speak in an admiring fashion, to be enthusiastic about. 

  • To make a soft murmuring sound, as a pigeon. 

intj
  • An expression of approval, fright, surprise, etc. 

adj
  • Cool. 

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