- the eighth part of a circle.
- Mathematics. any of the eight parts into which three mutually perpendicular planes divide space.
- an instrument having an arc of 24°, used by navigators for measuring angles up to 90°.
- the position of one heavenly body when 45° distant from another.
- (initial capital letter) Astronomy. the constellation Octans.
- any of the eight parts into which the three planes containing the Cartesian coordinate axes divide space
- an eighth part of a circle
- astronomy the position of a celestial body when it is at an angular distance of 45° from another body
- an instrument used for measuring angles, similar to a sextant but having a graduated arc of 45°
n.instrument for making angular measurements in navigation or astronomy, 1731, from Late Latin octans “the eighth part,” from octo “eight” (see octa-) on analogy of quadrant. In geometry, octant meant “the eighth part of a circle.”