octant: Meaning and Definition of

oc•tant

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.
5. (cap.)the constellation Octans.