octant
Pronunciation: /ˈɒkt(ə)nt/
noun
- an 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.
- each of eight parts into which a space or solid body is divided by three planes which intersect (especially at right angles) at a single point.
- an obsolete instrument in the form of a graduated eighth of a circle, used in astronomy and navigation.
Origin:
late 17th century: from Latin octans, octant- 'half-quadrant', from octo 'eight'