- an eighth of a circle; 45° angle or arc
- an instrument like the sextant, for measuring angles
- Astron. the position of one celestial body when it is 45° distant from another
- Math. any of the eight parts into which a space is divided by three planes intersecting at a single point and at right angles to one another
Origin of octantLate Latin octans, eighth part from Classical Latin octo, eight
- One eighth of a circle.
- a. A 45° arc.b. The area enclosed by two radii at a 45° angle and the intersected arc.
- An instrument based on the principle of the sextant but employing only a 45° angle, used as an aid in navigation.
- Astronomy The position of a celestial body when it is separated from another by a 45° angle.
- One of eight parts into which three-dimensional space is divided by three usually perpendicular coordinate planes.
Origin of octantLatin octāns octant- from octō eight ; see oktō(u) in Indo-European roots.