octant noun.
['ɒkt(ǝ)nt] L17.[Latin octant-, -ans half-quadrant, from OCTO-. Cf. QUADRANT noun1, SEXTANT.]1. Astrology &
Astronomy. The aspect of two planets which are one-eighth of a circle (45 degrees) apart in the sky;
spec. each of the four points at which the moon is 45 degrees from conjunction with or opposition to the sun. Cf.
OCTILE. Now
rare or
obsolete.
L17.2. An arc of a circle or of the horizon forming one-eighth of the whole; one-eighth of the area of a circle, contained within two radii at an angle of 45 degrees.
M18.b. Each of the eight parts into which a space or solid figure is divided by three planes (usually mutually at right angles) intersecting at the central point.
L18.3. An instrument in the form of a graduated eighth of a circle, used for making angular measurements, esp. in astronomy and navigation.
M18.4. (Usu.
Octant.)
The constellation Octans.
M19. ■ oc'tantal adjective L18. [TahlilGaran] English Dictionary ▲