| Abbreviation | Definition |
|---|---|
| ACES | Agility Conditioning Endurance And Strength |
| ACES | All Children Exercising Simultaneously |
| ACES | Attitude Cooperation Example Sportsmanship |
| ACES | Attitude, Citizenship, Effort, And Sportsmanship |
| ACFA | Alabama Coastal Fisherman's Association |
| ACFC | Aston Clinton Football Club |
| ACFC | Atherton Colleries Football Club |
| ACFC | Atlantic Central Football Conference |
| ACFF | Armored Core Formula Front Extreme Battle |
| ACFG | AC Football Group |
| ACFH | Alvernia College Field Hockey |
| ACFL | Action College Football League |
| ACFL | Atlantic Coast Football League |
| ACFN | American Council for Fitness and Nutrition |
| ACFO | Association of Camps Farthest Out |
| ACKD | Academy of Classical Karate Do |
| ACLG | All Canada Lacrosse Games |
| ACMC | American Cured Meat Championships |
| ACMG | Association of Canadian Mountain Guides |
| ACNA | Association Croquet North America |