| Term | Definition |
| hyper- | over, above, beyond the ordinary |
| hypo- | under, beneath, less than the ordinary |
| hyperacidity | excessive acidity |
| hypoacidity | weak acidity |
| hyperactive | overactive |
| hypoactive | underactive |
| hypertension | abnormally high blood pressure |
| hypotension | low blood pressure |
| hyperthyroid | marked by excessive activity of the thyroid gland |
| hypothyroid | marked by deficient activity of the thyroid gland |
| hyperbole | extravagant exaggeration of statement |
| hypertrophy | enlargement of a part or organ, as from excessive use (antonym, atrophy: lack of growth from want of nourishment or from disease) |
| hypodermic | injected under the skin |
| hypothesis | theory or supposition assumed as a basis for reasoning ("something placed under") |
| hypothetical | assumed without proof for the purpose of reasoning, assumed without proof for the purpose of reasoning; conjectural |
| endocrine | secreting internally |
| endoskeleton | internal skeleton or supporting framework in an animal |
| exoskeleton | hard protective structure developed outside the body, as the shell of a lobster |
| endo- | within |
| exo- | out of, outside |
| -archy | rule |
| anarchy | total absence of rule or government; confusion; disorder |
| autarchy | rule by an absolute sovereign |
| hierarchy | body of rulers or officials grouped in ranks, each being subordinate to the rank above it |
| matriarchy | form of social organization in which the mother rules the family or tribe, descent being traced through the mother |
| monarchy | state ruled over by a single person, as a king or queen |
| oligarchy | form of government in which a few people have the power |
| patriarchy | form of social organization in which the father rules the family or tribe, descent being tracecd through the father |
| geo- | earth, ground |
| geography | study of the earth's surface, climate, continents, people, products, etc. |
| geometry | mathematics dealing with lines, angles, surfaces, and solids (literally, "measurement of land") |
| geophysics | science treating of the forces that modify the earth |
| geopolitics | study of government and its policies as affected by physical geography |
| apogee | farthest point from the earth in orbit of a satellite |
| path | feeling; suffering; disease |
| antipathy | aversion ("feeling against"); dislike |
| apathy | lack of feeling, emotion, interest, or excitement; indifference |
| empathy | the complete understanding of another's feelings, motives, etc. |
| pathetic | arousing pity |
| pathos | quality in speech, writing, music, events etc., that arouse a feeling of pity or sadness |
| sympathy | a sharing of ("feeling with") another's trouble; compassion |
| telepathy | transference of the thoughts and feelings of one person to another by no apparent means of communication |
| homeopathy | system of medical practice that treats disease by administering minute doeses of a remedy which, if given to healthy persons, would produce symptons of the disease treated |
| osteopath | practitioner of osteopathy (treatment of diseases by manipulation of bones, muscles, neveres, etc.) |
| pathogenic | causing disease |
| pathological | due to disease |
| psychopathic | pertaining to mental disease; insane |
| morph | form |
| amorphous | without definite form; shapeless |
| metamorphosis | change of form |
| morphology | branch of biology dealing with the form and structure of animals and plants |
| peri- | around, about, near, enclosing |
| pericardium | membranous sac enclosing the heart |
| perimeter | the whole outer boundary or measurement of a surface or figure |
| periphery | outside boundary |
| periscope | instrument permitting those in a submarine a view ("look around") of the surface |
| peristyle | row of columns around a building or court; the space so enclosed |
| peritonitis | inflammation of the peritoneum (membrane lining the abdominal cavity and covering the organs) |