| AAT | Average Access Time |
|---|---|
| ABR | Average Bandwidth Requirement |
| AC | average cost (skr.), priemerné náklady (angl.skr.) |
| ADT | Average Daily Traffic |
| AEI | Average Efficiency Index |
| AER | Average Event Rate |
| ASR | Aquifer Storage and Recovery |
| ASR | Average Success Rate, indikátor z telefónie |
| ATC | average total cost (skr.), priemerné celkové náklady (angl.skr.) |
| CIE | Commission Internationale de l'Eclairage |