quadrature

 
Pronunciation: /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:

mid 16th century (as a mathematical term): from Latin quadratura 'a square, squaring', from quadrare (see quadrate)