| ODU | optical density unit |
|---|---|
| OES | oral esophageal stethoscope; optical emission spectroscopy |
| OF | occipitofrontal; open field [test]; optical fundus; orbitofrontal; osmotic fragility; osteitis fibro... |
| OPD | obstetric prediabetic; optical path difference; otopalatodigital [syndrome]; outpatient department; ... |
| OPS | operations; optical position sensor; osteoporosis-pseudolipoma syndrome; outpatient service; outpati... |