The Collaborative International Dictionary
Quadratrix \Quad*ra"trix\, n.; pl. -trixes, or -trices. [NL.] (Geom.) A curve made use of in the quadrature of other curves; as the quadratrix, of Dinostratus, or of Tschirnhausen.
Wiktionary
n. (context mathematics English) A curve having ordinates which are a measure of the area (or quadrature) of another curve.
Wikipedia
In mathematics, a quadratrix (from the Latin word quadrator, squarer) is a curve having ordinates which are a measure of the area (or quadrature) of another curve. The two most famous curves of this class are those of Dinostratus and E. W. Tschirnhausen, which are both related to the circle.
Usage examples of "quadratrix".
Eliza had sat next to him and pronounced their names: the Limaçon of Pascal, the Kampyle of Eudoxus, the Conchoid of de Sluze, the Quadratrix of Hippias, the Epitrochoid, Tractrix, and the Cassinian Ovals.