See Also: octant(medicine)
octant(dictionary)

octant (iou)



octant noun. L17.
[Latin octant-, -ans half-quadrant, from OCTO-. Cf. QUADRANT noun1, SEXTANT.]
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.
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.
An instrument in the form of a graduated eighth of a circle, used for making angular measurements, esp. in astronomy and navigation. M18.
(Usu. Octant.) The constellation Octans. M19.
oc'tantal adjective L18.