[ sek-stuh nt ]
/ ˈsɛk stənt /


an astronomical instrument used to determine latitude and longitude at sea by measuring angular distances, especially the altitudes of sun, moon, and stars.
(initial capital letter) Astronomy. the constellation Sextans.

Words nearby sextant

Origin of sextant

1590–1600; < Latin sextant- (stem of sextāns) sixth part of a unit. See sext1, -ant


sextant sextet sexton Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for sextant

British Dictionary definitions for sextant

/ (ˈsɛkstənt) /


an optical instrument used in navigation and consisting of a telescope through which a sighting of a heavenly body is taken, with protractors for determining its angular distance above the horizon or from another heavenly body
a sixth part of a circle having an arc which subtends an angle of 60°

Word Origin for sextant

C17: from Latin sextāns one sixth of a unit
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for sextant

[ sĕkstənt ]

An instrument containing a graduated 60° arc and a movable pivoted arm corresponding to the radius of the arc's circle, used in celestial navigation to measure the altitude of a celestial body in order to determine the observer's latitude and longitude. A horizontally mounted telescope and two small mirrors are arranged so that the observer can, by moving the pivoted arm, sight the horizon and the reflected image of the celestial body in the same line, giving a reading along the arc that is used to look up the observer's position in a published table.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.