chirl vs rocking

chirl

noun
  • A kind of musical warble. 

verb
  • To emit a low sound; to warble. 

rocking

noun
  • The abrading of a copper plate with a rocker, preparatory to mezzotinting. 

  • The motion by which the design on a steel mill is transferred to a copper cylinder. 

  • The motion of something that rocks. 

adj
  • Excellent; great. 

  • Shaking, swaying or moving back and forth. 

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