The position of the moon or an outer planet when the line joining it to the earth makes a right angle with a line joining the earth to the sun.
Mathematics
A method of quadrature is a numerical method that finds an approximation to a definite integral; in many cases, the integral may then be found by a limiting process. SeeGaussian quadrature, Simpson’s rule, trapezium rule.
Astronomy
The occasion when a body in the Solar System has an angular separation, or elongation, of 90° east or west of the Sun.
Computer
1. A method of signal modulation involving two carrier waves with a 90° phase difference. This allows better usage of the bandwidth of the communications link. Quadrature is used in higher-speed modems.
2.Seenumerical integration.
Electronics and Electrical Engineering
Two periodic quantities that have the same frequency and waveform are in quadrature when the phase difference between them is π/2 (90°). They therefore differ by one quarter of a period, one wave reaching its peak value when the other passes through zero.