heliometer

1 of 2

noun

he·​li·​om·​e·​ter ˌhē-lē-ˈä-mə-tər How to pronounce heliometer (audio)
: a visual telescope that has a divided objective designed for measuring the apparent diameter of the sun but also used for measuring angles between celestial bodies or between points on the moon
heliometric adjective
heliometrically adverb

heliometric

2 of 2

adjective

he·​lio·​met·​ric ¦hēlēō¦me‧trik How to pronounce heliometric (audio)
: of, employing, or obtained by use of a heliometer
heliometric observations
heliometric results
heliometrically adverb

Word History

Etymology

Noun

French héliomètre, from hélio- heli- entry 1 + -mètre -meter

Adjective

French héliométrique, from hélio- heli- entry 1 + -métrique -metric

First Known Use

Noun

1753, in the meaning defined above

Time Traveler
The first known use of heliometer was in 1753

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Cite this Entry

“Heliometer.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/heliometer. Accessed 27 Jun. 2026.

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