Also found in: Thesaurus, Encyclopedia, Wikipedia.
1. One eighth of a circle.
a. A 45° arc.
b. The area enclosed by two radii at a 45° angle and the intersected arc.
3. An instrument based on the principle of the sextant but employing only a 45° angle, used as an aid in navigation.
4. Astronomy The position of a celestial body when it is separated from another by a 45° angle.
5. One of eight parts into which three-dimensional space is divided by three usually perpendicular coordinate planes.
oc·tan′tal (ŏk-tăn′təl) adj.
1. (Mathematics) maths
a. any of the eight parts into which the three planes containing the Cartesian coordinate axes divide space
b. an eighth part of a circle
2. (Astronomy) astronomy the position of a celestial body when it is at an angular distance of 45° from another body
3. (Navigation) an instrument used for measuring angles, similar to a sextant but having a graduated arc of 45°
[C17: from Latin octans half quadrant, from octo eight]
1. the eighth part of a circle.
2. any of the eight parts into which three mutually perpendicular planes divide space.
3. an instrument having an arc of 24°, used by navigators for measuring angles up to 90°.
4. the position of one heavenly body when 45° distant from another.
oc•tan′tal (-ˈtæn tl) adj.
Switch to new thesaurus
|Noun||1.||octant - a measuring instrument for measuring angles to a celestial body; similar to a sextant but with 45 degree calibration|
limb - the graduated arc that is attached to an instrument for measuring angles; "the limb of the sextant"