Any self-regulating process by which a biological or mechanical system maintains stability while adjusting to changing conditions. Systems in dynamic equilibrium reach a balance in which internal change continuously compensates for external change in a feedback control process to keep conditions relatively uniform. An example is temperature regulation—mechanically in a room by a thermostat or biologically in the body by a complex system controlled by the hypothalamus, which adjusts breathing and metabolic rates, blood-vessel dilation, and blood-sugar level in response to changes caused by factors including ambient temperature, hormones, and disease.

Learn more about homeostasis with a free trial on Britannica.com.