1. the regulation by an organism of all aspects of its internal environment, including body temperature, salt–water balance (see osmoregulation), acid–base balance (see hydrogen-ion concentration), and blood sugar level. This involves monitoring changes in the external and internal environments by means of receptors and adjusting bodily processes accordingly. Compare tension law. [first described by Walter B. Cannon]

2. maintenance of a stable balance, evenness, or symmetry. —homeostatic adj.