or PM

Digital Technology.
noun plural pms, pm's.
  1. a private message sent to another user of a social media service or private messaging service: How do I send a pm to the moderator of the message board?
verb (used with object) pm'd or pmed, pm'ing, or pming.
  1. to send a private message to (another user of such a service).


Symbol, Chemistry.
  1. promethium.



  1. after noon.
  2. the period between noon and midnight.

Origin of p.m.

From the Latin word post merīdiem

Usage note

See a.m.


or PM Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for pm

siesta, teatime, autopsy, critique, review, PM, P.M.

Examples from the Web for pm

Contemporary Examples of pm

Historical Examples of pm

British Dictionary definitions for pm


abbreviation for
  1. premium


the internet domain name for
  1. St Pierre and Miquelon


the chemical symbol for
  1. promethium


abbreviation for
  1. Prime Minister
  2. Past Master (of a fraternity)
  3. Paymaster
  4. Postmaster
  5. military Provost Marshal


P.M., pm or PM

abbreviation for
  1. (indicating the time period from midday to midnight) post meridiemSee a.m.
  2. post-mortem (examination)

Word Origin for p.m.

(sense 1) Latin: after noon
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for pm


abbreviation of Latin post meridiem "after noon."

Online Etymology Dictionary, © 2010 Douglas Harper

pm in Medicine


  1. picometer


  1. The symbol for the elementpromethium
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

pm in Science


  1. The symbol for promethium.


  1. A radioactive metallic element of the lanthanide series. Promethium does not occur in nature but is prepared through the fission of uranium. It has 17 isotopes, one of which is used to make long-lived miniature batteries that work at extreme temperatures for up to five years. The longest-lived isotope, Pm 147, has a half-life of 2.5 years and is used as a source of beta rays. Atomic number 61; melting point 1,168°C; boiling point 2,460°C; valence 3. See Periodic Table.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.