# Octant

Octant
Three axial planes (x=0, y=0, z=0) divide space into eight equal octant domains, each with a coordinate signs from (-,-,-) to (+,+,+).

An octant is one of eight divisions.

## Octant in the plane

An 8-point windrose

Traditionally wind direction is given as one of the 8 octants (N, NE, E, SE, S, SW, W, NW) because that is more accurate than merely giving one of the 4 quadrants, and the wind vane typically does not have enough accuracy to bother with more precise indication.

## Octant in three-dimensional space

An octant is one of the eight divisions of a Euclidean three-dimensional coordinate system defined by the signs of the coordinates. It is similar to the two-dimensional quadrant and the one-dimensional ray. [1]

Usually, the octant with all three positive coordinates is referred to as the first octant. There is no generally used naming convention for the other seven octants.

• first octant (+, +, +)
• top-back-right (−, +, +)
• top-back-left (−, −, +)
• top-front-left (+, −, +)
• bottom-front-left (+, −, −)
• bottom-back-left (−, −, −)
• bottom-back-right (−, +, −)
• bottom-front-right (+, +, −)

## Multi-dimensional space

The multi-dimensional generalization of the octant is the orthant, also called hyperoctant. An n-dimensional space is divided into 2n hyperoctants.

## References

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### Look at other dictionaries:

• octant — OCTÁNT, octante, s.n. 1. Instrument de navigaţie maritimă şi aeriană sau care serveşte la măsurarea înălţimii aştrilor, a distanţelor lor unghiulare etc. 2. A opta parte din circumferinţa unui cerc sau dintr o suprafaţă circulară. ♦ Fiecare… …   Dicționar Român

• octant — [ ɔktɑ̃ ] n. m. • 1619; lat. octans « huitième partie » 1 ♦ Géom. Arc de 45° (huitième de cercle). 2 ♦ Mar. anc. Instrument du genre du sextant, mais dont le limbe n est que de 45°. ● octant nom masculin (latin octans, antis) Huitième partie du… …   Encyclopédie Universelle

• octant — (n.) instrument for making angular measurements in navigation or astronomy, 1731, from L.L. octans the eighth part, from octo eight (see OCTA (Cf. octa )) on analogy of QUADRANT (Cf. quadrant). In geometry, octant meant the eighth part of a… …   Etymology dictionary

• Octant — Oc tant, n. [L. octans, antis. fr. octo eight. See {Octave}.] 1. (Geom.) The eighth part of a circle; an arc of 45 degrees. [1913 Webster] 2. (Astron. & Astrol.) The position or aspect of a heavenly body, as the moon or a planet, when half way… …   The Collaborative International Dictionary of English

• Octant — (v. lat.), 1) (Spiegeloctant, Sphärischer O.), ein astronomisches, auch zur See gebräuchliches Instrument, der achte Theil eines Kreises, mit welchem man durch doppelte Reflexion Winkel messen kann; meistens wird es zum Messen der Sonnenhöhe… …   Pierer's Universal-Lexikon

• octant — [äk′tənt] n. [LL octans, eighth part < L octo,EIGHT] 1. an eighth of a circle; 45° angle or arc 2. an instrument like the sextant, for measuring angles 3. Astron. the position of one celestial body when it is 45° distant from another 4. Math.… …   English World dictionary

• Octant — Pour les articles homonymes, voir Octant (homonymie). Octant Vue de la constellation …   Wikipédia en Français

• octant — oktantas statusas T sritis Standartizacija ir metrologija apibrėžtis Kampinio atstumo tarp kosminių kūnų matuoklis. atitikmenys: angl. octant rus. октант, m pranc. octant, m ryšiai: susijęs terminas – kvadrantas susijęs terminas – kvadrantas… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

• octant — oktantas statusas T sritis Standartizacija ir metrologija apibrėžtis Kampų matuoklis. atitikmenys: angl. octant rus. октант, m pranc. octant, m ryšiai: susijęs terminas – kvadrantas susijęs terminas – kvadrantas susijęs terminas – kvadrantas… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

• octant — oktantas statusas T sritis Standartizacija ir metrologija apibrėžtis Viena iš aštuonių sričių, į kurias dalijama erdvė. atitikmenys: angl. octant rus. октант, m pranc. octant, m ryšiai: susijęs terminas – kvadrantas susijęs terminas – kvadrantas… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas