quadrature

noun

1. (countable, uncountable)The process of making something square; squaring.
2. (countable, uncountable)The act or process of constructing a square that has the same area as a given plane figure, or of computing that area.

   “1976, D. T. Whiteside (editor), The Mathematical Papers of Isaac Newton, Volume 7: 1691-1695, Cambridge University Press, page 3, Craige was then on the point of publishing a short tract wherein he expounded a systematic (if far from general) 'Method of determining the quadrature of figures comprehended by straight lines and curves', there gathering a variety of techniques of rational algebraic quadrature and arc-rectification […] .”

3. (countable, uncountable)The calculation of a definite integral by numerical means.

   “In this chapter, we present some example applications of the Gaussian quadrature methods discussed in the previous chapters.[…]Figure 4.1 shows the accuracy of the polynomial Gaussian quadratures used to evaluate the first two integrals as a function of N.”

   “The integral is thus given by a variant of the Fejér quadrature with two points at the interval boundaries, namely x₁ = −1 and x_N = 1 analogous to the Lobatto quadratures of the next section.”

4. (countable, uncountable)The act or process of solving an indefinite integral by symbolic means.
5. (countable, uncountable)A situation in which the directions of two celestial bodies (or a celestial body and the Sun) form a right angle from the perspective of the observer.

   “When the Moon is in quadrature, it appears in the sky as a half-moon.”

6. (countable, uncountable)The condition in which the phase angle between two alternating quantities is 90°.

   “If ν_(IN) has 50% duty-cycle, then the outputs are in quadrature.”

   “The total mmf in a synchronous machine may be split up into two components—one along the pole axis or direct axis and the other at right angles to this or the quadrature axis.[…]In the case of salient pole construction, however, the reluctances of the magnetic circuits on which the mmfs act are different along the direct axis and the quadrature axis.”

   “Quadrature LO generation is critical to the operation of direct-downconversion receivers [7]. Two common techniques for quadrature generation are divide-by-two frequency dividers, and polyphase filters.”

7. (countable, uncountable)A painting painted on a wooden panel.