| Term | Definition |
| GA | gastric analysis |
| gal | gallon |
| GB | gallbladder |
| Gc | gonococcus, gonorrhea |
| GH | growth hormone |
| Gl | gastrointestinal |
| Gm, g | gram |
| gr | grain |
| gt, gtt, gtts | drop, drops |
| GTT | glucose tolerance test |
| GU | genitourinary |
| Gyn | gynecolgy |
| H | hydrogen |
| H2O | water |
| H2O2 | hydrogen peroxide |
| H, (h), hypo | hypodermic injection |
| HA | hearing aid, headache |
| HBP | high blood pressure |
| HBV | hepatitis B virus |
| GTT | glucose tolerance test |
| GU | genitourinary |
| Gyn | gynecolgy |
| H | hydrogen |
| H2O | water |
| H2O2 | hydrogen peroxide |
| H, (h), hypo | hypodermic injection |
| HA | hearing aid, headache |
| HBP | high blood pressure |
| HBV | hepatitis B virus |
| HCG | human chorionic gonadotrophin |
| HC1 | hydrochloric acid |
| hct | hematocrit |
| HDL | high density lipoproteins |
| Hg | mercury |
| Hgb, Hb | hemoglobin |
| HHA | home health assistant/aide |
| HIV | human immunodeficiency virus (AIDs virus) |
| HMO | health maintenance organization |
| HOB | head of bed |
| HOH | hard of hearing |