| CO | carbon monoxide; cardiac output; castor oil; casualty officer; centric occlusion; cervical orthosis;... |
|---|---|
| SHCO | sulfated hydrogenated castor oil |
| ORS | olfactory reference syndrome; oral rehydration solution; oral surgery, oral surgeon; Orthopaedic Res... |
| OR | a logical binary relation that is true if any argument is true, and false otherwise; [o]estrogen rec... |
| OCP | octacalcium phosphate; ocular cicatricial pemphigoid; oral case presentation; oral contraceptive pil... |