re

re — preposition

1. used in formal letters, emails, and official documents to introduce the topic or

1.prepositionB1
Definition

used in formal letters, emails, and official documents to introduce the topic or subject that the message is about.

Example

Re your application for the marketing role, we would like to invite you for an interview next week.

re + noun phrase in formal letter opening

The envelope was marked 'Re: Account Number 4492' in bold letters on the front.

subject line format in business correspondence

Common collocations
  • re your + noun
  • re our + noun
  • re: [subject line]
Synonyms
  • regarding

    equally formal but more common in spoken English

  • concerning

    slightly more formal, used in both writing and speech

  • about

    neutral and widely used; less formal than 're'

Grammar Patterns

re + noun phrase

Usage Note

Frequently used in letter headings, memo subject lines, and legal documents. The topic noun phrase follows directly after 're' without a preposition.

Common Mistakes

Re: about your order
Re your order
do not add 'about' after 're'; the word 're' itself means 'about' or 'regarding'.

2. placed at the front of an email subject header when your message answers a previ

2.prepositionA2
Definition

placed at the front of an email subject header when your message answers a previous message that someone sent you.

Example

When Dario hit reply, the email system automatically added 'Re:' before the original subject.

automatic addition by email client

Naoko's inbox showed twelve messages all starting with 'Re: Budget Meeting'.

Common collocations
  • Re: + subject
  • Re: Re: + subject
  • remove the Re:
  • add Re:

Grammar Patterns

Re: + original subject line

Usage Note

Derived from Latin 'rēs' (thing, matter) via the same origin as the REGARDING sense, but now functions as a standard email convention. Some email clients display 'Re:' even when the message is forwarded rather than replied to.

Common Mistakes

Writing 'RE:' in all capital letters in the subject line
Writing 'Re:' with a capital R and lowercase e
this is the standard email convention in most systems.

re — noun

re — prefix

re — symbol

Word family

Synonym discussion

Sense: preposition/1

All four words introduce the topic of a discussion or document, but they differ in formality and context. 'Re' is the most restricted — it appears almost exclusively in written correspondence (letters, emails, memos, legal documents) and is never used in everyday speech. 'Regarding' and 'concerning' are formal but can appear in both writing and spoken presentations. 'About' is fully neutral and works in all registers. 'With reference to' is the wordiest form, typically found in very formal business letters. For example, in a casual conversation you would say 'about your idea,' never 're your idea'; in a memo heading you would write 'Re: New Policy,' not 'About: New Policy.'

about ↗regarding ↗concerningwith reference to

Common collocations

Nouns

  • re + [topic noun]
  • re your + [noun]
  • re: [subject line]

Phrases

  • re our conversation
  • re your letter
  • re: your request

Etymology

LatinEnglish

The word 're' in English has three distinct origins. The preposition (meaning 'regarding') comes from Latin 'rē', the ablative form of 'rēs' meaning 'thing, matter' — literally 'in the matter of.' This use appeared in English legal and business documents in the 1700s. The prefix (meaning 'again' or 'back') comes from a different Latin source: the prefix 're-' meaning 'again, back, anew,' which entered English through French and directly from Latin. The musical note 're' has a third origin: it was taken from the Latin word 'resonare' (to resound) in the medieval hymn 'Ut queant laxis,' where Guido of Arezzo created solfège syllables from the first letters of each phrase.