Related Clues:
- Abbr. indicating to whom it may concern
- Ltr.-routing aid
- Letters that help a letter sorter
- To on a fax
- "Oh, before I forget..." in Internet shorthand
- 'Oh, before I forget...' in Internet shorthand
- Mailers shorthand
- Letters on business letters
- Letter routing abbr.
- Start of a text-message afterthought
- Letter-routing abbr.
- Envelope shortening
- Letter-routing letters
- Chat room afterthought letters
- Memo header, for short