Definition of "heliostat" [he•li•o•stat]

• An instrument in which a mirror is automatically moved so that it reflects sunlight in a constant direction. It is used with a pyrheliometer to make continuous measurements of solar radiation. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "According to the report, it features over 1,000 freestanding heliostat mirrors that follow the arc of the sun."
• "The Pit Power Tower design has heliostat fields on both sides of the pit and so you need two receivers."
• "You also need to look at losses from suboptimal heliostat-receivers alignment resulting in further losses."