# Definition of quadrature in English:

## quadrature

### noun

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

‘Craig published several more papers on the logarithmic curve, the curve of quickest descent and quadrature of figures.’
• ‘He generalised Gauss's method of quadrature and expressed the polynomials which are involved as a determinant.’
• ‘This book is a treatise on infinite series, summation, interpolation and quadrature.’
• ‘He also considered curves of double curvature on the sphere and the quadrature of parts of a spherical surface.’
• ‘Both in-phase and quadrature measurements are recorded.’
• 2Astronomy
The position of the moon or a planet when it is 90° from the sun as viewed from the earth.

‘When the Sun-Moon system is in quadrature relative to the Earth, the combined gravitational forces are not as strong.’
• ‘The planet is at east quadrature (ninety degrees east of the Sun) on the 26th.’
• 3Electronics
A phase difference of 90° between two waves of the same frequency, as in the color difference signals of a television screen.

‘The MT312 is a single-chip variable rate digital quadrature phase shift keying satellite demodulator.’
• ‘The L5 signal that will appear with the Block IIF satellites in 2006, will have quadrature phase skip keying.’
• ‘The quadrupolar echo pulse sequence was employed using quadrature detection with complete phase cycling of the pulse pairs.’
• ‘It features RS - 422-compatible quadrature output, and programmable resolution and output frequency.’
• ‘A method and apparatus for equalizing a received quadrature amplitude modulated signal is disclosed.’

## quadrature

/ˈkwädrəCHər/ /ˈkwɑdrətʃər/

### Origin

Mid 16th century (as a mathematical term): from Latin quadratura ‘a square, squaring’, from quadrare (see quadrate).