A triple of three arbitrary vectors with common vertex (Altshiller-Court 1979), often called a trihedral angle since it determines three planes.
The vectors are often taken to be unit vectors, and the term trihedron is frequently encountered in the consideration of the unit orthogonal vectors given by 
, 
, and 
(tangent vector, normal vector, and binormal vector).
See also
Binormal Vector,
Centroidal Line,
Dihedral Angle,
Isoclinal Line,
Isoclinal Plane,
Normal Vector,
Orthocentric Line,
Tangent Vector Explore with Wolfram|Alpha
References
Altshiller-Court, N. "The Trihedral Angle." Ch. 2 in Modern Pure Solid Geometry. New York: Chelsea, pp. 27-41, 1979.Referenced on Wolfram|Alpha
Trihedron Cite this as:
Weisstein, Eric W. "Trihedron." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Trihedron.html
Subject classifications
