AY
| Acronym | Definition |
|---|---|
| AY | Academic Year |
| AY | Antarctica |
| AY | American Youth |
| AY | Angus Young (singer) |
| AY | Assessment Year (business/tax) |
| AY | Alliance Youth |
| AY | Aero Oy (formerly Finnair) |
| AY | Alienated Youth (band) |
| AY | Alien Youth (band) |
| AY | Y-Axis Acceleration |
| AY | Finnair, Oyj - Finland (IATA code) |
| AY | Alphatian Year (fictional, Dungeons & Dragons) |
| AY | Allegheny and Western Railway Company |