PM

'PM', 'Pm' or 'pm' can refer to:
In Science:

★ Post meridiem (also written P.M. and p.m.), Latin for "after noon" - this is used to disambiguate hours of the day, in the 12-hour clock system

★ Particulate matter, fine dust and soot suspended in the air

★ Permanent magnet

★ Petametre, a length unit (10¹⁵ m) (Pm)

★ Perl module

★ Phase modulation, in electrical engineering

★ Picometre, a length unit (10^-12 m) (pm)

★ Pilot Monitoring

★ Powdery mildew, a fungal disease that affects a wide range of plants

★ post mortem

★ Precious metal

★ Principia Mathematica, in set theory

★ Promethium, in chemistry (Pm)
In politics:

★ PM (newspaper), a politically leftist U.S. newspaper in the late 1940s and early 1950s

★ Pontifex Maximus, The Pope (P·M·)

★ Prime minister, in government

★ P.M. Pubblico Ministero Italian magistrate office

★ Saint-Pierre and Miquelon: ISO 3166-1 alpha-2 country code
In economy:

★ Phillip Morris

★ PM (Radio 4), a BBC Radio 4 newsmagazine

★ Pobjoy Mint, via its mint mark "PM"

★ Postmaster

★ Project manager or Project management
In literature:

★ Perry Mason

★ ''The Peoples of Middle-earth'' by Christopher Tolkien
Other:

★ Palm mute, in guitar tablature

★ Pere Marquette Railroad (AAR reporting mark PM)

★ Personal message or Private message, in the context of BBS's and Internet forums

★ Pistolet Makarova

★ Porch Monkey

★ Preventive maintenance, aka preventative maintenance, aka proactive maintenance

★ Tropic Air IATA airline designator