- variant of ad- before p: appear.
- variant of apo- before a vowel or h: aphelion.
- additional premium.
- author's proof.
- Apostle.
- Apothecaries'.
- April.
- account paid.
- accounts payable.
- authority to pay or purchase.
- son of: occurring as part of some surnames of Welsh origin
- Air Police
- Associated Press
- a variant of apo- aphelion
- (in prescriptions, etc) ante prandium