AP

UK: /eɪpiː /

WordReference Random House Learner's Dictionary of American English © 2025

AP, 

1. Associated Press.

Ap.,  an abbreviation of:

1. April.

A/P or a/p, an abbreviation of:

1. Business account paid.
2. Business accounts payable.
3. Business authority to pay or purchase.

WordReference Random House Unabridged Dictionary of American English © 2025

AP ,

1. Grammar See adjective phrase. 
2. Education [Trademark.] See Advanced Placement Program.
3. Military See Air Police. 
4. See American plan. 
5. Military antipersonnel.

Also, A.P. 
ap-¹ ,

1. var. of ad- before
   p: appear.

ap-² ,

1. var. of apo- before a vowel or
   h: aphelion.

Ap. ,

1. Apostle.
2. Apothecaries'.
3. April.

A/P ,

1. Business account paid.
2. Business accounts payable.
3. Business authority to pay or purchase.

Also, a/p 
a.p. ,

1. Business additional premium.
2. author's proof.

WordReference Random House Learner's Dictionary of American English © 2025

apo-, Compare ap-².
APO or A.P.O., an abbreviation of:

1. Stamps, Military Army Post Office.

WordReference Random House Unabridged Dictionary of American English © 2025

A•po  (ä′pô), n. 

1. Place Names an active volcano in the S Philippines, on S Mindanao: highest peak in the Philippines. 9690 ft. (2954 m).

apo-, 

1. a prefix occurring originally in loanwords from Greek, where it was joined to verbs, deverbal forms, and other parts of speech. Among its functions in Greek, apo- has the spatial sense "away, off, apart'' (apogee;
   apocope;
   apostasy;
   apostrophe);
   it occurs with deverbals that denote a response or defense (apodosis;
   apology) and is found on verbs having perfective force relative to a corresponding simple verb (apoplexy;
   aposiopesis). In modern scientific coinages in English and other languages, apo- marks things that are detached, separate, or derivative (apocarpous;
   apoenzyme).

Also,[esp. before a vowel,] ap-. 

• Greek, prefixal use of apó; akin to off, Sanskrit apa, Latin ab

A.P.O., 

1. Military Army & Air Force Post Office.

Also, APO 

Collins Concise English Dictionary © HarperCollins Publishers::

ap / æp/ prefix

1. son of: occurring as part of some surnames of Welsh origin: ap Thomas

Etymology: from Welsh mab son

Collins Concise English Dictionary © HarperCollins Publishers::

ap- prefix

1. a variant of apo-: aphelion

Collins Concise English Dictionary © HarperCollins Publishers::

apo-, ap- prefix

1. away from; off: apogee
2. indicating separation of: apocarpous

Etymology: from Greek apo away, off