Bible Dictionaries
Heliostat

Webster's Dictionary

(n.) An instrument consisting of a mirror moved by clockwork, by which a sunbeam is made apparently stationary, by being steadily directed to one spot during the whole of its diurnal period; also, a geodetic heliotrope.

Bibliography Information
Webster, Noah. Entry for 'Heliostat'. Noah Webster's American Dictionary. https://www.studylight.org/​dictionaries/​eng/​web/​h/heliostat.html. 1828.