posterior vs rear end

posterior

• The hinder parts of the body. 

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

• Following in order or in time. 

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

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

rear end

• The back or hindmost part of anything, such as a car. 

• The buttocks.