| Word | Definition |
| K | potassium |
| kal/i | potassium |
| kary/o | nucleus |
| kel/o | tumor, fibrous growth |
| keloid | An overgrowth of scar tissue that develops around a wound |
| kelp | A type of seaweed. |
| ken/o | empty |
| kerat/o | cornea, horny, hard |
| keratin | A family of fibrous proteins that are principle constituents of epidermis; hair; nails; horny tissues, and tooth enamel. |
| keratitis | Inflammation of the cornea |
| keratoconjunctivitis | Inflammation of the cornea and conjunctiva. |
| keratoconus | A conical protrusion of the central part of the cornea. |
| keratosis | Any horny growth of the skin such as a wart or callus. |
| ketonuria | Presence of ketone bodies in urine. |
| ketosis | Abnormally high concentration of ketone bodies, as in diabetes mellitus. |
| kg | kilogram |
| kidney | One of a pair of organs that filter blood for the secretion of urine and that regulates ion concentrations. |
| kilo- | one thousand |
| kilogram | Unit of mass equal to one thousand grams. |
| kinesi/o | movement |
| kinesics | The study of body position motion in communication. |
| kinesis | Movement of an organism in response to a stimulus |
| kinetics | The study of the interrelationships that exist between body parts and how those connections influence movement. |
| klept/o | to steal |
| kleptomania | An abnormal, strong impulse to steal. |
| km | kilometer |
| knee | The joint between inferior femur and superior |
| koil/o | hollow, concave |
| koilonychia | A disease of the fingernails, where they become thin and concave. |
| kraur/o | dry |
| KS | Kaposi sarcoma |
| KUB | kidney, ureter, and bladder |
| kv | kilovolt |
| KVO | keep vein open |
| kym/o | waves |
| kyph/o | bent, hump |
| kyphosis | Deformities of the spine characterized by an exaggerated convexity of the vertebral column. Sometimes called round back or hunchback. |