anterior vs backside

anterior

adj
  • Nearer the forward end, especially in the front of the body; nearer the head or forepart of an animal. 

  • Pronounced with an obstruction located in front of the palato-alveolar region of the mouth, e.g. b, p, d, t. 

  • (of a part of a flower or leaf) Situated further away from the mainstem. 

  • Coming before or earlier in time or development, prior to, preceding. 

backside

adj
  • Approaching an obstacle backward 

  • Used other than figuratively or idiomatically: see back, side. 

noun
  • Used other than figuratively or idiomatically: see back, side. 

  • The back side of an estate: the backyard and outbuildings behind a main house, especially (UK dialect, euphemistic) an outhouse. 

  • The reverse or opposite of anything. 

  • A person's buttocks. 

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