in electronics, a phase difference of 90 degrees between two waves of the same frequency, as in the colour difference signals of a television screenSubmitted by: Ahmed Al-Quzweeni from United Kingdom on 26/12/2018
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maths
the process of constructing a square with an area equal to that of a circle, or of another figure bounded by a curveSubmitted by: Ahmed Al-Quzweeni from United Kingdom on 26/12/2018
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astronomy
the position of the moon or a planet when it is 90° from the sun as viewed from the earth.Submitted by: Ahmed Al-Quzweeni from United Kingdom on 26/12/2018