| RIS | radiology information system; rapid immunofluorescence staining; resonance ionization spectroscopy |
|---|---|
| 'Greek letter alpha' | angular acceleration; first [carbon atom next to the carbon atom bearing the active group in organic... |
| AO | abdominal aorta; achievement orientation; acid output; acridine orange; ankle orthosis; anodal openi... |
| DOA | date of admission; dead on arrival; Department of Agriculture; depth of anesthesia; differential opt... |
| DOS | day of surgery; deoxystreptamine; disk operating system; Doctor of Ocular Science; Doctor of Optical... |