A plane parallel to two (or more) skew lines, also called a director plane. The orientation of a director is fixed, but it is specified uniquely only if a point lying on it is also specified.

A director of two skew lines is perpendicular to the line of shortest distance of these two lines (Altshiller-Court 1979, p. 1).

Altshiller-Court, N. Modern Pure Solid Geometry. New York: Chelsea, p. 1, 1979.

CITE THIS AS:

Weisstein, Eric W. "Director." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/Director.html