[witch of Agne.si] n [Maria Gaetana Agnesi d. 1799 Ital. mathematician; witch, trans. of It versiera cubic curve (influenced by It versiera female demon)] (1875): a plane cubic curve that is symmetric about the y-axis and approaches the x-axis as an asymptote that is constructed by drawing lines from the origin intersecting an upright circle tangent to the x-axis at the origin and taking the locus of points of intersection of pairs of lines parallel to the x-axis and y-axis each pair of which consists of a line parallel to the x-axis through the point where a line through the origin intersects the circle and a line parallel to the y-axis through the point where the same line through the origin intersects the line parallel to the x-axis through the point of intersection of the circle and the y-axis and that is given by an equation whose left side is x squared multiplied by y and whose right side consists of the factor (2a - y) multiplied by
4. times the square of a--called also witch