| OCH | oral contraceptive hormone |
|---|---|
| OCM | oral contraceptive medication |
| OCS | occipital condyle syndrome; Ondine's curse syndrome; open canalicular system; oral contraceptive ste... |
| OCT | object classification test; optimal cutting temperature; oral contraceptive therapy; ornithine carba... |
| OES | oral esophageal stethoscope; optical emission spectroscopy |