quadrant /ˈkwɒdr(ə)nt 
/ ▸ noun 1 technical each of four quarters of a circle. ▪ each of four parts of a plane, sphere, space, or body divided by two lines or planes at right angles: the right upper quadrant of the kidney.
2 historical an instrument used for taking angular measurements of altitude in astronomy and navigation, typically consisting of a graduated quarter circle and a sighting mechanism. 3 a frame fixed to the head of a ship's rudder, to which the steering mechanism is attached. ▪ a panel with slots through which a lever is moved to orient or otherwise control a mechanism.
– DERIVATIVES quadrantal /kwɒˈdrantl / adjective – ORIGIN late Middle English (denoting the astronomical instrument): from Latin quadrans, quadrant- ‘quarter’, from quattuor ‘four’.
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