What is the meaning of pm?

noun

• An examination and dissection of a dead body to determine cause of death or the changes produced by disease.
  • synonyms: autopsy, necropsy, postmortem, post-mortem, postmortem examination, post-mortem examination
• A soft silvery metallic element of the rare earth group having no stable isotope; was discovered in radioactive form as a fission product of uranium.
  • synonyms: promethium, atomic number 61
• The person who holds the position of head of the government in the United Kingdom.
  • synonyms: Prime Minister, premier
• Modulation of the phase of the carrier wave.
  • synonyms: phase modulation