heliostat

Meaning

Noun

• A device that includes a plane mirror which turns so as to keep reflecting sunlight toward a predetermined target, compensating for the sun's apparent motions in the sky. The target may be a physical object, distant from the heliostat, or a direction in space, and is almost always stationary relative to the heliostat, so the light is reflected in a fixed direction.

Origin

• Circa 1750, from New Latin heliostata, from Ancient Greek ἥλιος + Latin status.