PM (also written pm) often means "after noon" in the 12-hour clock (Latin Post meridiem).
PM or Pm may also refer to:
- Particulate matter, particulates — fine dust and soot — suspended in the air
- PM10, particulates, smaller than 10 μm, that can cause health problems
- PM3 (chemistry), or Parameterized Model number 3 - a modelling method in computational chemistry
- Permanent magnet, an object which stays magnetised without external effort or mason.
- Perpetual motion, refers to movement that goes on forever
- Petameter, a length unit (1015 m) (Pm)
- Phase modulation, in electrical engineering
- PM tube, Photomultiplier tube.
- Picometre, a length unit (10−12 m) (pm)
- Plasma membrane, is a selectively permeable lipid bilayer found in all cells
- Powdery mildew, a fungal disease that affects a wide range of plants
- Powder metallurgy, a method of fabricating metals.
- Premolar tooth, dental nomenclature
- Promethium, chemical element number 61 (Pm)
- Polymyositis, disease
- Post mortem, a medical examination carried out after death
- Principia Mathematica, a three-volume work on the foundations of mathematics
- Polarization-maintaining optical fiber
- Participatory medicine, a new model of medicine
Computing and Internet
- Pac-Man, character, video game, and TV series
- Paper Mario, game for Nintendo 64
- Particle Mesh, an algorithm for calculating the potential of a system (used in computational physics).
- Perl module, a discrete component of software for the Perl programming language. (file extension .pm)
- Perl mongers - groups of local Perl enthusiasts.
- Personal message or private message, a type of e-mail within community sites or chat between two people.
- PM-38, Soviet light mortar
- PM-43, Finnish anti-personnel mine
- PM-63 RAK, Polish submachine gun
- PM-60, East German anti-tank mine
- PM-68, Finnish anti-personnel mine
- PM-79, Bulgarian anti-personnel mine
- PM-84 Glauberyt, Polish submachine gun
- PM md 96, Romanian submachine gun
- Makarov PM (Pistolet Makarova), a 1940s, Soviet pistol
- Minebea PM-9, Japanese submachine gun
- 2PM, a seven-member boy band from South Korea
- 4 P.M., an American male R&B group
- Palm mute, a playing technique for the guitar or bass guitar
- Penn Masala, a Hindi a cappella group from the University of Pennsylvania, USA
- P.M. Dawn, American hip-hop act
- Power Metal, a sub-genre of heavy metal music.
- PM-1, American nuclear reactor.
- Preventive maintenance, a job for fault prevention during machine executes before occurring some problems.
- Palace Museum, a large art museum housed in the Forbidden City in Beijing
- Polar Medal, a medal awarded by the Sovereign of the United Kingdom
- Saint Pierre and Miquelon: ISO 3166-1 alpha-2 country code
- .pm, the country code top level domain (ccTLD) for Saint Pierre and Miquelon
- Performance management: activities to ensure that goals are consistently being met in an effective and efficient manner.