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1. One eighth of a circle.
a. A 45° arc.
b. The area enclosed by two radii at a 45° angle and the intersected arc.
3. An instrument based on the principle of the sextant but employing only a 45° angle, used as an aid in navigation.
4. Astronomy The position of a celestial body when it is separated from another by a 45° angle.
5. One of eight parts into which three-dimensional space is divided by three usually perpendicular coordinate planes.
oc·tan′tal (ŏk-tăn′təl) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
1. (Mathematics) maths
a. any of the eight parts into which the three planes containing the Cartesian coordinate axes divide space
b. an eighth part of a circle
2. (Astronomy) astronomy the position of a celestial body when it is at an angular distance of 45° from another body
3. (Navigation) an instrument used for measuring angles, similar to a sextant but having a graduated arc of 45°
[C17: from Latin octans half quadrant, from octo eight]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
1. the eighth part of a circle.
2. 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.
oc•tan′tal (-ˈtæn tl) adj.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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|Noun||1.||octant - a measuring instrument for measuring angles to a celestial body; similar to a sextant but with 45 degree calibration|
limb - the graduated arc that is attached to an instrument for measuring angles; "the limb of the sextant"
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