| AO | abdominal aorta; achievement orientation; acid output; acridine orange; ankle orthosis; anodal openi... |
|---|---|
| APN | acute pyelonephritis; advanced practice nurse; average peak noise |
| APR | abdominoperineal resection; absolute proximal reabsorption; acute phase reaction or reactant; amebic... |
| ARIMA | autoregressive integrated moving average |
| ARL | Association of Research Libraries; average remaining lifetime |