1. The act of squaring; the finding of a square having the same area as some given curvilinear figure; as, the quadrature of a circle; the operation of finding an expression for the area of a figure bounded wholly or in part by a curved line, as by a curve, two ordinates, and the axis of abscissas.
  2. A quadrate; a square.
  3. The integral used in obtaining the area bounded by a curve; hence, the definite integral of the product of any function of one variable into the differential of that variable.
  4. The position of one heavenly body in respect to another when distant from it 90ยก, or a quarter of a circle, as the moon when at an equal distance from the points of conjunction and opposition.