The torsional stiffness of a ski or board is it's ability of it to resist diagonal twisting along its length. A torsionally stiff ski/ board will hold an edge better through high-speed turns and chopped up snow. A torsionally softer ski or board will be more forgiving and manoeuvreable at lower speeds.
A moment (in.-lb.) or displacement around the longitudinal centerline of the bellows - twisting. Although bellows can react a limited amount of torsion they are not designed for torsional displacement, or to react torsional moments. Should not be confused with Angular Rotation.
Twisting of an organ on its vascular pedicle, risking necrosis. Can happen to the testis in boys, especially after an injury to the scrotum, or to the ovary and fallopian tube, either spontaneously during adolescence or when enlargement from superovulation has produced ovarian hyperstimulation syndrome (OHSS). An operation to untwist it can save the affected organ, if carried out quickly enough.
The twisting of the testis inside the scrotum. Besides causing extreme pain and swelling, the rotation twists off the blood supply and causes severe damage to the testicle. Torsion of the ovary may also occur in a woman suffering from hyperstimulation, a complication of ovulation induction treatment.
In topology, torsion is the name for certain topological invariants that behave similarly to the algebraic torsion (subgroups of finite-order elements) of homology groups. Examples include the Reidemeister-Schreier torsion of a group acting on a finite complex; and also the analytic torsion defined using Laplacians.
In abstract algebra, the notion of torsion relates to commutative modules. Let R be a commutative ring and M an R-module. An element of m is called a torsion element if there is a non-zero divisor in R such that r annihilates m (i.e. rm=0).