The common perpendicular to two opposite edges of a tetrahedron.
Bialtitude
See also
Altitude, Bimedian, TetrahedronExplore with Wolfram|Alpha
References
Altshiller-Court, N. Modern Pure Solid Geometry. New York: Chelsea, p. 50, 1979.Referenced on Wolfram|Alpha
BialtitudeCite this as:
Weisstein, Eric W. "Bialtitude." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Bialtitude.html