| OP | occipitoparietal; occipitoposterior; occiput posterior; octapeptide; olfactory peduncle; opening pre... |
|---|---|
| opg | opening |
| OS | left eye [Lat. oculus sinister]; occipitosacral; occupational safety; office surgery; Omenn syndrome... |
| PAo | airway opening pressure; ascending aortic pressure; pulmonary artery occlusion pressure |
| Po | opening pressure |