octant

American  

[ok-tuhnt] / ˈɒk tənt /

noun

1. the eighth part of a circle.

2. Mathematics. 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. Astronomy. Octant, the constellation Octans.

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octant British  

/ ˈɒktənt /

noun

1. maths

   1. any of the eight parts into which the three planes containing the Cartesian coordinate axes divide space

   2. an eighth part of a circle

2. astronomy the position of a celestial body when it is at an angular distance of 45° from another body

3. an instrument used for measuring angles, similar to a sextant but having a graduated arc of 45°

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Other Word Forms

• octantal
  adjective

Etymology

Origin of octant

First recorded in 1680–90; from Latin octant- (stem of octāns ); see Octans

Example Sentences

See Examples For:

octant

We can use a similar method to visualizing a vector field in ℝ2 by choosing points in each octant.

From Textbooks ● Mar. 30, 2016

Find the volume of the solid situated in the first octant and bounded by the planes x + 2y = 1, x = 0, y = 0, z = 4, and z = 0.

From Textbooks ● Mar. 30, 2016

Find the maximum volume of a rectangular box with three faces in the coordinate planes and a vertex in the first octant on the plane x + y + z = 1.

From Textbooks ● Mar. 30, 2016

Find the volume of the solid situated in the first octant and determined by the planes z = 2, z = 0, x + y = 1, x = 0, and y = 0.

From Textbooks ● Mar. 30, 2016

She was in her octant, and her crescent was clearly outlined on the dark background of the sky.

From The Moon-Voyage by Verne, Jules