The act of squaring; the reducing of a figure to a square. Thus the finding of a square which shall contain just as much area as a circle or a triangle, is the quadrature of that circle or triangle.

A quadrate; a square.

In astronomy, the aspect of the moon when distant from the sun 90 degrees or a quarter of the circle; or when the moon is at an equal distance from the points of conjunction and opposition. Quadrature of curves, in mathematics, the finding of rectilineal figures containing the same areas as figures bounded by curved lines.