jounce vs somersault

jounce

noun
  • A movement, such as a jolt or a shake. 

  • The fourth derivative of the position vector with respect to time; the time derivative of jerk. 

verb
  • To jolt; to shake, especially by rough riding or by driving over obstructions. 

somersault

noun
  • Starting on one's feet, an instance of rotating one's body 360 degree while airborne or on the ground, with one's feet passing over one's head. 

verb
  • To perform a somersault. 

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