| OR | a logical binary relation that is true if any argument is true, and false otherwise; [o]estrogen rec... |
|---|---|
| ORS | olfactory reference syndrome; oral rehydration solution; oral surgery, oral surgeon; Orthopaedic Res... |
| OS | left eye [Lat. oculus sinister]; occipitosacral; occupational safety; office surgery; Omenn syndrome... |
| OS | 1) Opening Snap 2) Orthopedic(Osteo)-Surgery; 정형 외과 3) Ocu... |
| AAOS | American Academy of Orthopedic Surgeons |