| Abbreviation | Definition |
|---|---|
| APTN | Australian Professional Tester Network |
| APTR | Association for Prevention Teaching and Research |
| APTS | Association of Public Television Stations |
| APUA | Alliance for Prudent Use of Antibiotics |
| AQP | Air Quality Program |
| AQR | Association for Qualitative Research |
| AR | American Rivers |
| AR | Another Rainbow |
| ARA | American Rheumatism Association |
| ARAA | AIDS Research Alliance of America |
| ARABACC | Arab American and Chaldean Council |
| ARABS | Arabian Riders And Breeders Society |
| ARC | Adoption Resource Center |
| ARC | Advocacy for Respect for Cyclists |
| ARC | Allied Rainbow Communities |
| ARC | American Red Cross |
| ARC | Animal Rescue Center |
| ARC | Animal Rights Conference |
| ARC | Association for Retarded Children |
| ARC | Association for Retarded Citizens |