/kwod"reuh cheuhr, -choor'/, n.1. the act of squaring.2. Math.a. the act or process of finding a square equal in area to a given surface, esp. a surface bounded by a curve.b. the act or process of finding an area or calculating an integral, esp. by numerical methods.c. a definite integral.3. Astron.a. the situation of two heavenly bodies when their longitudes differ by 90°.b. either of the two points in the orbit of a body, as the moon, midway between the syzygies.c. (of the moon) those points or moments at which a half moon is visible.4. Electronics. the relation between two signals having the same frequency that differ in phase by 90°.[1545-55; < L quadratura, equiv. to quadrat(us) (ptp. of quadrare; see QUADRATE) + -ura -URE]
* * *in astronomy, that aspect of a heavenly body in which its direction as seen from the Earth makes a right angle with the direction of the Sun. The Moon at First or Last Quarter is said to be at east or west quadrature, respectively. A superior planet (outside the Earth's orbit) is at west quadrature when its position is 90° west of the Sun. It rises around midnight, reaches the meridian (a great circle on the celestial sphere, passing through the north and south poles and the zenith) near sunrise and sets near noon. At east quadrature the planet is near the meridian at sunset and sets near midnight. At both quadratures the planet is at gibbous phase (more than half but not all of the disk illuminated), but only Mars shows up conspicuously gibbous.in mathematics, the process of determining the area of a plane geometric figure by dividing it into a collection of shapes of known area (usually rectangles) and then finding the limit (as the divisions become ever finer) of the sum of these areas. When this process is performed with solid figures to find volume, the process is called cubature. A similar process called rectification is used in determining the length of a curve. The curve is divided into a sequence of straight line segments of known length. Because the definite integral of a function determines the area under its curve, integration is still sometimes referred to as quadrature.
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