"instrument that keeps something stationary," before 1970, shortened form of L. statim (adv.), originally "to a standstill," from status (see state). The combining form -stat used in devices for stabilizing (thermostat, etc.) is from Gk. statos "standing, stationary," from
histanai "to cause to stand," from PIE base *sta- "to stand" (see stet). First used in heliostat "an instrument for causing the sun to appear stationary" (1742).