| Term | Definition |
| I&D | incisions and drainage |
| I&O | intake and output |
| ICCU | intensive coronary care unit |
| ICD | international classification of diseases |
| ICU | intensive care unit |
| ID | intradermal |
| IDDM | insulin-dependent diabetes mellitus |
| IH | infectious hepatits |
| IM | intramuscular |
| imp | impression |
| in | inch |
| inf | infusion, inferior, infection |
| ing | inguinal |
| inj | injection |
| int | internal, interior |
| IPPB | intermittent positive pressure breathing |
| irr, irrig | irrigation |
| Isol, isol | isolation |
| IT | inhalaton therapy |
| IUD | intrauterine device |
| IV | intravenous |
| IVP | intravenous pyelogram |
| jt | joint |
| K | potassium |
| KCL | potassium chloride |
| Kg, kg | kilogram |
| KUB | kidney, ureter, bladder X-ray |