| Term | Definition |
| hyper | over, above, beyond ordinary |
| hypo | under, beneath, less than the ordinary |
| hyperacidity | excessive acidity |
| hypoglycemia | abnormally low level of sugar in the blood |
| hypertension | abnormally high blood pressure |
| hypotension | low blood pressure |
| hyperthermia | especially high fever |
| hypothermia | subnormal body temperature |
| hyperbole | exaggerated statements or claims not meant to be taken literally |
| hypersensitive | excessively sensitive; supersensitive |
| hypertrophy | enlargement of a body part or organ, as from excessive use |
| hypodermic | injected on the skin |
| hypothetical | assumed without proof for the purpose of reasoning; an opinion or conclusion formed on the basis of incomplete information |
| Endo | within |
| exo | out of, outside |
| endogamy | marriage within the tribe, caste, or social group |
| exogamy | marriage outside the tribe, caste, or social group |
| endogenous | produced from within; due to internal causes |
| exogenous | produced from without; due to external causes |
| endoskeleton | internal skeleton or supporting framework in an animal |
| exoskeleton | hard protective structure developed outside of the body |
| endoparasite | a parasite living in the internal organs of an animal |
| exoteric | external, exterior; readily understandable |
| exotic | introduced from a foreign; not native; excitingly strange |