| Term | Definition |
| hyper | over |
| hypo | under |
| hyperacidity | excessive acidity |
| hypoacidity | weak acidity |
| hyperglycemia | excess of sugar in the blood |
| hypoglycemia | abnormally low level of sugar in the blood |
| hyper/hypotension | high/low blood pressure |
| hyperthermia | especially high fever |
| hypothermia | subnormal body temperature |
| hyper/hypothyroid | excessive/deficient activity of the thyroid gland |
| hyperactive | overactive |
| hyperbole | exaggeration of statement |
| hypercritical | overcritical |
| hyperemia | super abundance of blood |
| hyperopia | super sensitive |
| hypertrophy | enlargement of a body part or organ from excessive use |
| hypodermic | injected under the skin |
| hypothesis | theory or supposition assumed as a basis for reasoning |
| hypothetical | assumed without proof for the purpose of reasoning |