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 ME torcion wringing one's bowels < OF torsion < LL torsiōn- (s. of torsiō) torment, equiv. to tors(us) twisted (see torse) + -iōn--ion
The stress or deformation caused when one end of an object is twisted in one direction and the other end is held motionless or twisted in the opposite direction.
[Middle English torcion, wringing pain in the bowels, from Old French torsion, from Late Latin torsiō, torsiōn-, a wringing pain, variant of Latin tortiō, from tortus, past particple of torquēre, to twist; see torsade.] tor'sion·al adj., tor'sion·al·ly adv.
c.1425, "wringing pain in the bowels," from O.Fr. torsion (1314), from L.L. torsionem (nom. torsio) "a wringing or gripping," from L. tortionem (nom. tortio) "torture, torment," from tortus, pp. of torquere "to twist" (see thwart). Meaning "action or process of twisting as by opposing forces" is first recorded 1543.
Main Entry: tor·sion Pronunciation: 'tor-sh&n Function: noun 1: the twisting of a bodily organ or part on its own axis torsion> 2: the twisting or wrenching of a body by the exertion of forces tending to turn one end or part about a longitudinal axis while the other is held fast orturned in the opposite direction; also: the state of being twisted —tor·sion·al/'tor-shn&l, -sh&n-&l/adjective