| Abbreviation | Definition |
|---|---|
| OP | osteopontin |
| OPD | obstructive pulmonary disease |
| OPD | orphan products development |
| OPD | otopalatodigital |
| OPD | Out Patient Department |
| OPD | outpatient department |
| OPG | ocular plethysmography |
| OPG | Office of the Paymaster General |
| OPG | oocysts per gram (of faeces) |
| OPG | optic pathway glioma |
| OPP | ocular perfusion pressure |
| OPP | organophosphate pesticides |
| OPP | organophosphate poisoning |
| OPP | outpatient with procedure |
| OPP | oxygen partial pressure |
| OPT | ocular photodynamic therapy |
| OPT | opisthotonos |
| OPT | optic pathway tumour |
| OPT | optician |
| OPT | oral provocation test |