From King Dictionary of Contemporary English
Related topics: Chronology
p.m.p.m. (also pm British English) /piː ˈem/ ●●● W2 TMCused after numbers expressing the time, to show that it is between noon and midnighta.m. The meeting starts at 2.30 pm.
Related topics: Officials
PMPM /ˌpiː ˈem/ noun [countable] British English informalPGO the Prime Minister a meeting with the PM
Origin p.m. (1600-1700) Latin post meridiem after noon