List of email subject abbreviations

This is a list of commonly and uncommonly used abbreviations which are used in the subject of an English email header.

Standard prefixes

These prefixes are usually inserted by the email client.

RE: or "Re:" followed by the subject line of a previous message indicates a reply to that message. This is not an abbreviation but stands for "in re", the Latin for "in the matter of".^[1]
- re (the ablative of res 'thing') has been used in English since the 18th century to mean 'in the matter of', 'referring to', 'regarding', or 'about'.^[2] In business letters and memoranda, "Re:" may be used instead of "Subject:" to set off the topic.^[3]
FW: a forwarded message. Also written as "FWD: ", "Fwd: " or "Fw: ". The recipient is informed that the email was originally sent to someone else, and that person has in turn forwarded a copy of the email to him or her.
FYI: "for your information". Also written as "Fyi: ". The recipient is informed that he does not have to reply to this email.

Standard non-prefixes

These words are inserted in the middle of or at the end of the subject, usually by the author.

WAS: the subject was changed. Not an abbreviation, but the word "was" (past tense of "be"). Also written as "Was: " and "was: ". It indicates that the subject has changed since the previous email, e.g., "Do you know a good babysitter? (WAS: What should we do this weekend?)". This prevents confusion on the part of the recipient and avoids accusations of threadjacking.
OT: off topic. Used within an email thread to indicate that this particular reply is about a different topic than the rest of the thread, in order to avoid accusations of threadjacking.
EOM – end of message. Also written as "Eom" or "eom". Used at the end of the subject when the entire content of the email is contained in the subject and the body remains empty. This saves the recipient's time because they then do not have to open the message.

Software development

The following prefixes are often used in software development:

[ANNOUNCE], [ANN] – announcement. A new version of the software has been released.
[BUG] – bug report. A description of an error in the software.
[PATCH] – software patch. New code is attached to or included in the body of the message.

Other English abbreviations

This is a list of abbreviations which are less commonly used in the subject of an English email header:

AB, meaning Action By. Used with a time indicator to inform the recipient that the sender needs a task to be completed within a certain deadline, e.g. AB+2 meaning Action By 2 days.

AR, meaning Action Required. The recipient is informed that she is being given a task.

FYA, meaning For Your Action. The recipient is informed that she is being given a task. Can also mean For Your Amusement, For Your Attention, For Your Approval, For Your Assistance, For Your Awareness, For Your Authorization, or For Your Acknowledgement.

FYIP, meaning For Your Information Please. The recipient is informed about the content in email with repect/Amiable sense.

FYSA, meaning For Your Situational Awareness. The recipient is informed that this information may be important context for other communications but contains no action required. Similar to FYI but used heavily in U.S. government and military email correspondence.

FYFG, meaning For Your Future Guidance. Also written as Fyfg. Used at the beginning of the subject, typically in corporate emails in which management wants to inform personnel about a new procedure they should follow.

FYG, meaning For Your Guidance. Also written as Fyg. Used at the beginning of the subject, typically in corporate emails in which management wants to inform personnel about a new procedure they should follow.

I, meaning Information. Used at the beginning of the subject. The recipient is informed that he does not have to reply to this email. May be more commonly used in Europe than in North America, where FYI may be preferred.

LET, meaning Leaving Early Today. Used in corporate emails to indicate that the sender will be leaving the office early that day.

LSFW, meaning Less Safe For Work. Used in corporate emails to indicate that the content may be sexually explicit or profane, helping the recipient to avoid potentially objectionable material.

NIM, meaning No Internal Message. Used when the entire content of the email is contained in the subject and the body remains empty. This saves the recipient's time because she then does not have to open the email.

NLS, meaning Not Life-Safe. Used to indicate that the content may be shocking or grotesque, helping the recipient to avoid potentially objectionable material.

NM, meaning No Message. Also written as N/M, n/m, or *n/m*. Used when the entire content of the email is contained in the subject and the body remains empty. This saves the recipient's time because she then does not have to open the email.

NMP, meaning Not My Problem. Used in a reply to indicate that the previous email has been ignored.

NMS, meaning Not Mind-Safe. Used to indicate that the content may be shocking or grotesque, helping the recipient to avoid potentially objectionable material.

NNTO, meaning No Need To Open. The recipient is informed that the/she does not need to open the email, necessary information is in the Subject line.

NNTR, meaning No Need To Respond. The recipient is informed that he does not have to reply to this email.

NRN, meaning No Reply Necessary or No Reply Needed. The recipient is informed that he does not have to reply to this email.

NRR, meaning No Reply Requested or No Reply Required. The recipient is informed that he does not have to reply to this email.

NSFW, meaning Not Safe For Work or Not Suitable For Work. Used in corporate emails to indicate that the content may be sexually explicit or profane, helping the recipient to avoid potentially objectionable material.

NSS, meaning Not School-Safe or Not School-Suitable. Used in school network emails to indicate that the content may be sexually explicit or profane, helping the recipient to avoid potentially objectionable material.

NT, meaning No Text. Also written as N/T or n/t. Used when the entire content of the email is contained in the subject and the body remains empty. This saves the recipient's time because she then does not have to open the email.

NWR, meaning Not Work Related. Used in corporate emails to indicate that the content is not related to business and therefore that the recipient can ignore it if desired.

NWS, meaning Not Work-Safe or Not Work-Suitable. Used in corporate emails to indicate that the content may be sexually explicit or profane, helping the recipient to avoid potentially objectionable material.

OoO, meaning Out of Office. Used in corporate emails to indicate that the sender will not be at work.

PFA, meaning [Please Find the Attachment]. Used in corporate emails to indicate that a document or set of documents is attached for the reference.

PNFO, meaning Probably Not For the Office. Used in corporate emails to indicate that the content may be sexually explicit or profane, helping the recipient to avoid potentially objectionable material.

PNSFW, meaning Probably Not Safe For Work or Possibly Not Safe For Work. Used in corporate emails to indicate that the content may be sexually explicit or profane, helping the recipient to avoid potentially objectionable material.

PYR, meaning Per Your Request. The recipient is informed that the sender is replying to a previous email in which she was given a task.

QUE, meaning Question. The recipient is informed that the sender wants an answer to this e-mail.

RB, meaning Reply By. Used with a time indicator to inform the recipient that the sender needs a reply within a certain deadline, e.g. RB+7 meaning Reply By one week (7 days).

RLB, meaning Read later. Used when sending personal or informational email to a business email address. Immediate response not required.

RR, meaning Reply Requested or Reply Required. The recipient is informed that he should reply to this email.

RSVP, meaning Reply Requested, please, from the French Répondez s'il vous plaît. The recipient is informed that he should reply to this email. Often used for replies (accept/decline) to invitations.

SFW, meaning Safe For Work. Used in corporate emails to indicate that although the subject or content may look as if it is sexually explicit or profane, it is in fact not.

SIM, meaning Subject Is Message. Used when the entire content of the email is contained in the subject and the body remains empty. This saves the recipient's time because she then does not have to open the email.

SSIA, meaning Subject Says It All. Used when the entire content of the email is contained in the subject and the body remains empty. This saves the recipient's time because she then does not have to open the email. A [1] at the start of the subject line, meaning "one-liner", means the same. Also EOM, above.

TLTR, meaning Too Long to read. Used in some corporate emails to request that the email sender re-writes the email body shorter

TBF, meaning (1) To be Forwarded. Used in some corporate emails to request that the email receiver should forward the mail to some one else. It also has the more common meaning (2) To be Frank/Fair. Usually only used in the email body.

TSFW, meaning Technically Safe For Work or Totally Safe For Work. Used in corporate emails to indicate that although the subject or content may look as if it is sexually explicit or profane, it is in fact not.

WFH, meaning Working From Home. Used in corporate emails to indicate that the referenced person is working from a remote location, usually a home office.

Y/N, meaning Yes/No. The recipient is informed that he should reply to this email with a simple yes or no answer, increasing the likelihood for the sender of getting a quick response. cf. VSRE, meaning Very Short Reply Expected.

Abbreviations in other languages

Email subject abbreviations in languages other than English.

Note that e-mail clients, when replying, may not recognize anything but "Re" when deciding whether or not to add a "Re:" in front of the subject. This means that a conversation between two participants can build up convoluted subject lines like "Re: AW: Re: AW: ..". To avoid this, translation of "Re" should be avoided, but also because the translation might not be understood by other parties whereas "Re" is universally recognized.

Language	RE	FW
Chinese (Traditional/Simplified)	回覆/回复	轉寄/转发
Danish	SV (Svar)	VS (Videresendt)
Dutch	Antw (Antwoord)	Doorst (Doorsturen)
Finnish	VS (Vastaus)	VL (Välitetty)
French	RE (Réponse)	TR (Transfert)
German	AW (Antwort)	WG (Weitergeleitet)
Greek	ΑΠ (Απάντηση) or ΣΧΕΤ (Σχετικό)	ΠΡΘ (Προωθημένο)
Hebrew	תגובה	הועבר
Italian	R or RIF (Riferimento)	I (Inoltro)
Icelandic	SV (Svara)	FS (Framsenda)
Indonesian	BLS (Balas)	TRS (Terusan)
Norwegian	SV (Svar)	VS (Videresendt)
Swedish	SV (Svar)	VB (Vidarebefordrat)
Spanish	RE (Responder)	RV (Reenviar)
Portuguese	RE (Resposta)	ENC (Encaminhado)
Polish	Odp (Odpowiedź)	PD (Podaj dalej)
Turkish	YNT (Yanıt)	İLT (İlet)

References

↑ RFC 5322
↑ Oxford English Dictionary s.v. 're'
↑ Clyde Winfield Wilkinson, et al., Communicating through letters and reports p. 19