The tritangent of a cubic surface is a plane which intersects the surface in three mutually intersecting lines. Each intersection of two lines is then a tangent point of the surface.
Tritangent
See also
Cubic SurfaceExplore with Wolfram|Alpha
References
Hunt, B. "Algebraic Surfaces." http://www.mathematik.uni-kl.de/~hunt/drawings.html.Referenced on Wolfram|Alpha
TritangentCite this as:
Weisstein, Eric W. "Tritangent." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Tritangent.html