An Etymological Dictionary of Astronomy and Astrophysics

An instrument consisting of a mirror moved by clockwork for tracking the movement of the Sun and reflecting the sunlight into a stationary solar telescope. A heliostat is similar to a → coelostat.

Etymology (EN): Heliostat, from → helio- + -stat
prefix denoting something that stabilizes, keeps, fixes, from -stata, from Gk. -states “one that causes to stand,” or statos “standing,” from *sta- “to stand.”

Etymology (PE): Hurdâštâr, from hur-, → helio- + dâštâr “holder, maintainer,” from dâštan “to hold, maintain; to have; to possess;” Mid.Pers. dâštan; O.Pers./Av. dar- “to hold, keep back, maintain, keep in mind;” cf.
Skt. dhr-, dharma- “law;” Gk. thronos “elevated seat, throne;” L. firmus “firm, stable;” Lith. daryti “to make;” PIE base *dher- “to hold, support.”