quadrature



the process of constructing a square with an area equal to that of a circle, or of another figure bounded by a curve.

the position of the moon or a planet when it is 90° from the sun as viewed from the earth.

a phase difference of 90 degrees between two waves of the same frequency, as in the colour difference signals of a television screen.

Click here to see the free dictionary definition for quadrature

definition by Oxford Dictionaries