Full forms: chat, letters and everyday

49 full forms, each with a line on what it means.

Two very different groups meet on this page. The first is old: Latin short forms that have been used in English writing for centuries, such as e.g., i.e., etc., AM, PM and RSVP. People use them daily without knowing the words behind them, and mix up e.g. with i.e. The second group is new: the short forms of text messages and social media, from ASAP and FYI in office mail to LOL and BRB in chats. The first group is fine in formal writing; the second is not, and should be kept out of applications, examination answers and letters to people you do not know well.

Explained in full: OK AM and PM RSVP

• OK

  no certain full form

  The most widely accepted origin is "oll korrect", a joke spelling of "all correct" from Boston newspapers of 1839.

  OK explained Copy

• ASAP

  As Soon As Possible

  Used to ask for something urgently.

  Copy

• FYI

  For Your Information

  Used when passing on something the reader should know.

  Copy

• RSVP

  Répondez s'il vous plaît

  French for "please reply", printed on invitations to ask guests to say whether they will come.

  RSVP explained Copy

• PS

  Postscript

  A note added after the end of a letter. From the Latin post scriptum, "written after".

  Copy

• NB

  Nota Bene

  Latin for "note well", used to draw attention to something important.

  Copy

• e.g.

  Exempli gratia

  Latin for "for example".

  Copy

• i.e.

  Id est

  Latin for "that is".

  Copy

• etc.

  Et cetera

  Latin for "and the rest".

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• vs

  Versus

  Latin for "against".

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• AM

  Ante meridiem

  Latin for "before midday": the hours from midnight to noon.

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• PM

  Post meridiem

  Latin for "after midday": the hours from noon to midnight.

  Copy

• AD

  Anno Domini

  Latin for "in the year of the Lord", used for years counted forward from the traditional date of the birth of Christ.

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• BC

  Before Christ

  Used for years counted backwards from the same date.

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• CE

  Common Era

  A neutral name for the same years as AD.

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• BCE

  Before Common Era

  A neutral name for the same years as BC.

  Copy

• RIP

  Rest in Peace

  Said or written of someone who has died. From the Latin requiescat in pace.

  Copy

• DOB

  Date of Birth

  The day on which a person was born.

  Copy

• ID

  Identity Document

  A card or paper that proves who a person is; in everyday use, short for identity or identification.

  Copy

• VIP

  Very Important Person

  A person given special treatment because of rank or fame.

  Copy

• DIY

  Do It Yourself

  Making or repairing things oneself.

  Copy

• ATM

  At The Moment

  A chat short form. As a machine, ATM is an automated teller machine.

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• BTW

  By The Way

  Used to add a side remark.

  Copy

• IDK

  I Don't Know

  A chat short form.

  Copy

• IMO

  In My Opinion

  Used before giving a personal view.

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• LOL

  Laughing Out Loud

  Shows that the writer found something funny.

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• BRB

  Be Right Back

  Says the writer is stepping away for a moment.

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• TTYL

  Talk To You Later

  A way of ending a chat.

  Copy

• OMG

  Oh My God

  Shows surprise.

  Copy

• TBH

  To Be Honest

  Used before a frank remark.

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• DM

  Direct Message

  A private message on a social media app.

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• PFA

  Please Find Attached

  Used in email to point to an attached file.

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• TBD

  To Be Decided

  Used for a detail not yet fixed.

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• NA

  Not Applicable

  Written in a form where a question does not apply. It can also mean not available.

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• PTO

  Please Turn Over

  Written at the foot of a page to show that it continues overleaf.

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• c/o

  Care of

  Used in an address when a letter is sent to someone at another person's address.

  Copy

• w.e.f.

  With effect from

  Used in notices to give the starting date of a change.

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• wrt

  With respect to

  Used in letters to mean "about" or "concerning".

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• GM

  Good Morning

  A greeting in chat. In business, GM means general manager.

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• GN

  Good Night

  A parting greeting in chat.

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• HBD

  Happy Birthday

  A short birthday greeting.

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• TY

  Thank You

  A short way to thank someone.

  Copy

• SOS

  no full form

  The international distress signal in Morse code. The letters were chosen because they are easy to send, not as initials; "Save Our Souls" was attached later.

  Copy

• GIF

  Graphics Interchange Format

  On chat apps, a short looping moving picture.

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• FOMO

  Fear Of Missing Out

  The worry that others are enjoying something without you.

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• AKA

  Also Known As

  Used before another name of a person or thing.

  Copy

• TGIF

  Thank God It's Friday

  Said at the end of the working week.

  Copy

• PJ

  Poor Joke

  Indian slang for a weak joke.

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• ISO

  In Search Of

  Used in online posts by someone looking for something.

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How to read an entry

The letters in bold are the short form as it is normally written. Under it is the full form, and then a line of meaning in plain words. Where the same letters mean something else in another field, the entry mentions it. "Copy" puts the short form, the full form and the meaning on your clipboard, ready to paste into notes or a message.

Check what matters. These pages explain names and terms in general. Rules, dates, fees and limits change: take them from the official body. Read on 12 November 2026.

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