| Mo | mitral opening |
|---|---|
| MVO | maximum venous outflow; mitral valve opening or orifice |
| 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... |