heliostat

H4E1L1I1O1S1T1A1T1

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.

OriginNew Latin heliostata ← Ancient Greek ἥλιος ← Latin status →
Scrabble 12
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Meanings

nounheliostat (plural heliostats)

plural heliostats

  1. 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.

    Each heliostat can be directed to bathe a particular park bench or tree in a beam of light. […] The three heliostats cost $355,000 together, not apiece.

    2005 June 2, Timothy Williams, “INK; Here Comes the Sun, Redirected”, in The New York Times, archived from the original on 29 May 2015
    1 more example

    In reply, the clockwork heliostats that had tracked the sun to reflect light into the indoor areas during the day now swivelled towards the street lamp to do the same for the night.

    2024, Jasper Fforde, Red Side Story, Hodder & Stoughton, page 90

Origin

  1. Latinstatus“stationary”
  2. Ancient Greekἥλιος“sun”
  3. New Latinheliostata
  4. Englishheliostat

First use appear c. 1747, from New Latin heliostata, from Ancient Greek ἥλιος (hḗlios, “sun”) + Latin status (“stationary”). By surface analysis, helio- + -stat.

More words from New Latin, Ancient Greek, Latin

Full word history & related roots →

Translations

Catalan heliòstat
  • heliòstatdevice to continuously reflect sunlight toward a predetermined target, almost always in some fixed direction, despite the sun's motions in the sky
French héliostat
  • héliostatdevice to continuously reflect sunlight toward a predetermined target, almost always in some fixed direction, despite the sun's motions in the sky
German Heliostat
  • Heliostatdevice to continuously reflect sunlight toward a predetermined target, almost always in some fixed direction, despite the sun's motions in the sky
Icelandic sólarhald
  • sólarhalddevice to continuously reflect sunlight toward a predetermined target, almost always in some fixed direction, despite the sun's motions in the sky
Italian eliostato
  • eliostatodevice to continuously reflect sunlight toward a predetermined target, almost always in some fixed direction, despite the sun's motions in the sky
Spanish heliostato, helióstato
  • heliostatodevice to continuously reflect sunlight toward a predetermined target, almost always in some fixed direction, despite the sun's motions in the sky
  • helióstatodevice to continuously reflect sunlight toward a predetermined target, almost always in some fixed direction, despite the sun's motions in the sky
Cite this entry
APA

heliostat. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/heliostat

MLA

“heliostat.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/heliostat. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “heliostat,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/heliostat.

Source: heliostat on Wiktionary, CC BY-SA 4.0.