Enter a clue or pattern or both:
The Clue
Business-letter term (4 letter answer)
The Answer
INRE
Tags
Notes
The answer INRE is very common and appears about once every 33 puzzles.
Related Clues
About
Anent
Apropos of
Concerning
Regarding
With respect to
Respecting
About, in legalspeak
About, on a memo
Brief start
Concerning, on a memo
Dictator's phrase
Legal phrase
Memo header
Memo opener
Memo starter
Memo words
Phrase usually before a colon