Definition for QUAD'RANT

QUAD'RANT, n. [L. quadrans, a fourth.]

  1. The fourth part; the quarter. – Brown.
  2. In geometry, the quarter of a circle; the arc of a circle containing ninety degrees; also the space or area included between this arc and two radii drawn from the center to each extremity. – Encyc.
  3. An instrument for taking the altitudes of the sun or stars, of great use in astronomy and navigation. Quadrants are variously made, but they all consist of the quarter of a circle whose limb is divided into ninety degrees; or, as in Hadley's reflecting quadrant, an arc of forty-five degrees is made to serve the same purpose as an arc of ninety degrees. Quadrant of altitude, an appendage of the artificial globe, consisting of a slip of brass of the length of a quadrant of one of the great circles of the globe, and graduated. It is fitted to the meridian and movable round to all points of the horizon. It serves as a scale in measuring altitudes, azimuths, &c. – Encyc.

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