| AR | absolute risk; accounts receivable; achievement ratio; actinic reticuloid [syndrome]; active resista... |
|---|---|
| ARI | acute respiratory illness; airway reactivity index; anxiety reaction, intense |
| ASM | acid sphingomyelinase; airway smooth muscle; American Society for Microbiology; anterior scalenus mu... |
| aw | airway; water activity |
| AWP | airway pressure; any willing provider; average of the wholesale prices; average wholesale price |