Definition of octant in English:

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octant

Pronunciation: /ˈäktənt/

noun

1An arc of a circle equal to one eighth of its circumference, or the area enclosed by such an arc with two radii of the circle.
Example sentences
  • Included in those downloads are the last two octants needed to complete the color, 360-degree ‘mission success' panorama.
  • The arc was extended from an octant to a sextant and a stout handle was added at the back of the instrument.
1.1Each of eight parts into which a space or solid body is divided by three planes that intersect (especially at right angles) at a single point.
Example sentences
  • At the octant (eight-cell) stage the embryo proper and suspensor are clearly distinct.
  • The model put forward for the action of BDL suggests that auxin is involved in determining hypophyseal cell fate at the octant stage.
1.2An obsolete instrument in the form of a graduated eighth of a circle, used in astronomy and navigation.
Example sentences
  • Instead of compasses, octants, and two-pole chains, modern digital GPS units determine position and direction.
  • Clark used celestial observation to determine latitude, triangulating position with an octant.

Origin

Late 17th century: from Latin octans, octant- 'half-quadrant', from octo 'eight'.

For editors and proofreaders

Syllabification: oc·tant

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