quadrature — ODE

quadrature /ˈkwɒdrətʃə

▸ noun [mass noun]

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

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

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

– ORIGIN late Middle English (denoting squareness): from Latin quadratura ‘division of land into squares’, from quadrare (see quadrate).