confocal quadrics
1Confocal — Con*fo cal, a. (Math.) Having the same foci; as, confocal quadrics. [1913 Webster] …
2Ellipsoid — This article is about the shape. For the type of theatrical spotlight, see ellipsoidal reflector spotlight. For the surface that approximates the figure of the Earth, see reference ellipsoid. triaxial redirects here. For the electrical cable, see …