posterior vs rearward

posterior

adj
  • Next to, or facing the main stem or axis. 

  • Following in order or in time. 

  • Relating to or denoting presentation of a fetus in which the rear or caudal end is nearest the cervix and emerges first at birth. 

noun
  • The hinder parts of the body. 

  • The probability that a hypothesis is true (calculated by Bayes' theorem). 

rearward

adj
  • Toward the back or rear of something. 

noun
  • The last troop; the rear of an army; a rear guard. 

  • The part that comes last or is situated in the rear; conclusion, wind-up. 

adv
  • Toward the back or rear of something. 

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