| Term | Definition |
| hyperacidity | excessive acidity |
| hypoacidity | low acidity |
| hyperglycemia | excess of sugar in the bloodstream |
| hypoglycemia | lack of sugar in the bloodstream |
| hypertension | abnormally high blood pressure |
| hypotension | low blood pressure |
| hyperthermia | high fever |
| hypothermia | subnormal body temp |
| hyperthyroid | mark by excessive activity of the thyroid gland |
| hypothyroid | mark by deficient activity of the thyroid gland |
| hyperactive | overactive |
| hyperbole | exageration |
| hypercritical | overly critical |
| hyperemia | superabundance of blood |
| hyperopia | farsightedness |
| hypersensitive | very sensitive |
| hypertrophy | enlargement of a body part from excessie use |
| hypodermic | injected under the skin |
| hypothesis | theory |
| hypothetical | assumed without proof |
| heteroclite | deviating from the common rule |
| heterodox | opposed to accepted beliefs |