| AAP | Alternate Access Provider |
|---|---|
| AAS | Alternate Architecture Study |
| ABBADIA | talianska operná speváčka (Luigia, 1821-1896) |
| ABBOTT | americká operná speváčka - sopranistka (Emma, 1850-1891) |
| ABC | Alternative Birth Center |
| ABP | Alternating Bit Protocol |
| ABS | Alternative Bank Schweiz, švajčiarska banka so sídlom v Oltene |
| ABS | Alternative Billing Service |
| AC | alternating current (skr.), striedavý prúd (angl.skr.) |
| ACI | alliance Cooperative Internationale (skr.) |