| Term | Definition |
| OS | left eye |
| os | mouth |
| OT | occupational therapy (or therapist) |
| Oto | otology (study of) |
| O2, OU | both eyes |
| OU | each eye |
| oz | ounce |
| P | pulse |
| Pap | Papanicoloau (smear) |
| paren | parenterally |
| Path | pathology |
| PC, pc | after meals |
| PD | postprandial (after meals) |
| PE | physical examination |
| Peds | pediatrics |
| pH | hydrogen ion concentration |
| PICU | pulmonary intensive care unit: pediatric intensive care unit |
| PID | pelvic inflammatory diease |
| PMP | previous menstrual period |
| PO | orally (per os) |
| post-op, p/o | after operation |
| pp | postprandial |
| pre-op | before operation |
| prep | prepare |
| prn | as required |
| PT | physical therapy (physical therapist) |
| pt | patient |
| PVC | premature ventricular contraction |
| q | every |
| qd | every day |
| qh | every hour |
| q2h | every two hour |
| QID,qid | four times a day |
| qm, qam | every morning |
| qn | every night |
| qns | quantity not sufficient |
| qs | quantity sufficient |
| R | respiration |
| RD | respiratory disease |
| REM | rapid eye movement |
| RN | registered nurse |
| RNA | ribonucleic acid (like DNA) |
| ROM | range of motion |
| Rx | prescription |
| s- | without |
| SICU | surgical intensive care unit |
| SOB | short(ness) of breath |
| SOS | if necessary |
| sp. gr. | specific gravity |
| Staph | Staphlococcus |
| stat | immediately |
| STD | sexually transmitted disease |
| Strep | Streptococcus |
| subcu., SC | subcutaneous |
| T | temperature |
| T & A | tonsillectomy and adenoidectomy |
| TB | tuberculosis |
| THR | total hip replacement |
| TIA | transient ischemic attack |
| TID, tid | three times a day |
| TPN | total parenteral nutrition |
| TPR | temperature, pulse, and respiration |
| URI | upper respiratory infection |
| UTI | urinary tract infection |
| VA | visual acuity |
| VD | veneral disease |
| wt | weight |
| x | multiplied by |