Meaning of Frenet formula

Fre•net' for"mula

Pronunciation: (fre-nā'), [key]
— Math. Math.
  1. one of a set of formulas for finding the curvature and torsion of a plane or space curve in terms of vectors tangent or normal to the curve.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.