sex·​tant ˈsek-stənt How to pronounce sextant (audio)
: an instrument for measuring angular distances used especially in navigation to observe altitudes of celestial bodies (as in ascertaining latitude and longitude)

Illustration of sextant

Illustration of sextant

Examples of sextant in a Sentence

Recent Examples on the Web Black Spy stares at the moon through an elaborate sextant, adjusting various settings and making mental calculations, finally drawing an X on the ground with a compass before setting the bucket down. Gyasi Hall, Longreads, 12 Sep. 2023 But otherwise, the astronauts’ situation was similar enough to that of Earthly sailors to use similar technology, which means instead of a marine sextant, astronauts used a space sextant. Amy Shira Teitel, Discover Magazine, 15 June 2019 The sextant used by the captain of the rescue ship Carpathia sold for just under $97,000 in 2016. James Rogers, Fox News, 1 Nov. 2020 The space sextant had two lines of sight, one fixed and one movable. Amy Shira Teitel, Discover Magazine, 15 June 2019 Chow's sextant, a navigation instrument that measured celestial objects and the horizon -- the only navigation device at that time -- was useless. Maggie Hiufu Wong, CNN, 23 Aug. 2021 The astrodome included a hanging point for a sextant so navigators would not have to hold the weighty instrument. David Hambling, Popular Mechanics, 25 Apr. 2021 For centuries, using a sextant, a sailor could mark a ship’s location by making a few calculations to determine a star’s position relative to the horizon. David Hambling, Popular Mechanics, 25 Apr. 2021 One, a rally in the Northeast sextant’s King School Park. oregonlive, 5 Sep. 2020 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'sextant.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


New Latin sextant-, sextans sixth part of a circle, from Latin, sixth part, from sextus sixth

First Known Use

1628, in the meaning defined above

Time Traveler
The first known use of sextant was in 1628

Dictionary Entries Near sextant

Cite this Entry

“Sextant.” Dictionary, Merriam-Webster, Accessed 28 Feb. 2024.

Kids Definition


sex·​tant ˈsek-stənt How to pronounce sextant (audio)
: a navigational instrument for measuring the angle between the horizon and the sun or a star in order to find out the latitude (as of a ship)

More from Merriam-Webster on sextant

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!