Definition of "quadrant" []

• Mathematics A circular arc of 90°; one fourth of the circumference of a circle. (noun)
• Mathematics The plane area bounded by such an arc and two perpendicular radii. (noun)
• Mathematics Any of the four areas into which a plane is divided by the reference axes in a Cartesian coordinate system, designated first, second, third, and fourth, counting counterclockwise from the area in which both coordinates are positive. (noun)
• A machine part or other mechanical device that is shaped like a quarter circle. (noun)
• An early instrument for measuring altitude of celestial bodies, consisting of a 90° graduated arc with a movable radius for measuring angles. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "As we all know, the Delta quadrant is the setting of Voyager, a series best not spoken of."
• "You will notice that the upper-quadrant is the only light that does not flash red."
• "Basing an intellectual circle around the quadrant is like rejecting the science, technology and ideas of democracy and equality of opportunity that arose through that age, stating a clear preference for the Old Ways."