1. a navigational instrument used to measure angles, especially the altitude of celestial bodies
Usage: nautical; astronomy
2. one of eight equal parts of a circle or sphere
Usage: geometry
3. any of the eight divisions of three-dimensional space formed by three coordinate planes
Usage: mathematics

Examples

• The navigator used an octant to determine the ship’s position at sea.
• Early sailors relied on octants before sextants became more common.
• The sphere was divided into eight octants for the geometry problem.
• Each octant represents one-eighth of the total volume.
• In three-dimensional coordinate systems, each octant has specific sign patterns.
• The astronomer measured the star’s altitude using a precision octant.