| OC | obstetrical conjugate; occlusocervical; office call; on call; only child; optic chiasma; oral contra... |
|---|---|
| O2cap | oxygen capacity |
| OCD | obsessive compulsive disorder; Office of Child Development; Office of Civil Defense; osteochondritis... |
| O2D | oxygen delivery |
| ODC | oritidine decarboxylase; ornithine decarboxylase; oxygen dissociation curve |