Anti-pedophile activism

Americanist Phonetic Alphabet

Amateur Press Association

Southern Athabaskan languages (excluding Navajo), from their ISO 639 code

APA style, a writing format developed by the above

American Psychological Association; also

American Psychiatric Association

ARCAM Private Army

Administrative Procedure Act, an American statute controlling government agency actions

Anglican Province of America

American Poolplayers Association

Australian Progressive Alliance

American Philological Association

American Philosophical Association

Apache Railway, from its Association of American Railroads reporting mark

a type of sword named after the village; see Bronze Age sword

Centennial Airport, Arapahoe County, Colorado, United States, from its IATA airport code

Allied Pilots Association

Ap (water), a Sanskrit word for water

American Pale Ale

American Planning Association

Advance Pricing Agreement

American Protective Association, an American anti-Catholic organization during the Gilded Age

Asian Pacific American

Hong Kong Academy for Performing Arts

Army Prosecuting Authority

Apa, Satu Mare, a commune in Satu Mare County, Romania

Antagonist Perpetrated Aggression, a martial arts combat system

Australian Postgraduate Awards

Japan Advertising Photographers' Association

All Points Addressable

American Psychopathological Association

Appa, a Nepali Sherpa and famous Mt. Everest mountaineer

Acolytes Protection Agency, a former professional wrestling tag-team