p.m. vs post mortem

p.m.

adv
  • after death 

  • after noon (used after a time to indicate it is between noon and midnight, i.e., in the afternoon, evening or night as opposed to the morning) 

post mortem

adv
  • Occurring after death. 

noun
  • An investigation of a corpse to determine the cause of death. 

  • Any investigation after the conclusion of an activity, particularly when said activity produces an unwanted outcome. 

adj
  • Having been inflicted or having occurred after death. 

How often have the words p.m. and post mortem occurred in a corpus of books? (source: Google Ngram Viewer )