means the process by which a living system keeps its internal conditions — temperature, pH, blood sugar, and the rest — stable and balanced despite whatever the outside world throws at it.

from Coined in the 1920s by American physiologist Walter Cannon, who stitched together two Greek pieces: homoios, "similar" or "same," and stasis, "standing still" — literally "staying the same." Cannon chose homoios rather than homos ("identical") on purpose, to signal that the body holds steady within a range rather than at one frozen point. It's a cousin of words like homogeneous and stasis itself.