Real Dictionary

homeostasis in American English
the tendency to maintain, or the maintenance of, normal, internal stability in an organism by coordinated responses of the organ systems that automatically compensate for environmental changes
noun: the tendency of a system, esp. the physiological system of higher animals, to maintain internal stability, owing to the coordinated response of its parts to any situation or stimulus tending to disturb its normal condition or function

homeostasis in British English
noun: the maintenance of metabolic equilibrium within an animal by a tendency to compensate for disrupting changes