caboose vs posterior

caboose

noun
  • buttocks 

  • The person or team in last place. 

  • A youngest child who is born after a long gap in time. 

  • A small sand-filled container used as an oven on board ship. 

  • The last car on a freight train, having cooking and sleeping facilities for the crew; a guard’s van. 

posterior

noun
  • The hinder parts of the body. 

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

adj
  • 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. 

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