the twisting of a body by two equal and opposite torques.
b.
the internal torque so produced.
4.
Mathematics.
a.
the degree of departure of a curve from a plane.
b.
a number measuring this.
Origin: 1375–1425; 1535–45 for def. 1;late Middle English torcion wringing one's bowels < Old French torsion < Late Latin torsiōn- (stem of torsiō) torment, equivalent to tors(us) twisted (see torse) + -iōn--ion