Torsion may refer to:

Science

Torsion (mechanics) In the field of solid mechanics, torsion is the twisting of an object due to an applied torque. Torsion could be defined as strain or angular deformation, and is measured by the angle a chosen section is rotated from its equilibrium position. Th ...

, the twisting of an object due to an applied torque * Torsion of spacetime, the field used in

Einstein–Cartan theory In theoretical physics, the Einstein–Cartan theory, also known as the Einstein–Cartan–Sciama–Kibble theory, is a classical theory of gravitation, one of several alternatives to general relativity. The theory was first proposed by Élie C ...

and **

Alternatives to general relativity Alternatives to general relativity are physical theories that attempt to describe the phenomenon of gravitation in competition with Einstein's theory of general relativity. There have been many different attempts at constructing an ideal theory o ...

Torsion angle In stereochemistry, a torsion angle is defined as a particular example of a dihedral angle, describing the geometric relation of two parts of a molecule joined by a chemical bond. Every set of three non-colinear atoms of a molecule defines a half ...

, in chemistry

Biology and medicine

* Torsion fracture or spiral fracture, a bone fracture when torque is applied * Organ torsion, twisting that interrupts the blood supply to that organ: ** Splenic torsion, causing

splenic infarction Splenic infarction is a condition in which blood flow supply to the spleen is compromised, leading to partial or complete infarction (tissue death due to oxygen shortage) in the organ. Splenic infarction occurs when the splenic artery or one of ...

Ovarian torsion Ovarian torsion (OT) or adnexal torsion is an abnormal condition where an ovary twists on its attachment to other structures, such that blood flow is decreased. Symptoms typically include pelvic pain on one side. While classically the pain is su ...

Testicular torsion Testicular torsion occurs when the spermatic cord (from which the testicle is suspended) twists, cutting off the blood supply to the testicle. The most common symptom in children is sudden, severe testicular pain. The testicle may be higher tha ...

* Penile torsion, a congenital condition * Torsion of the digestive tract in some domestic animals: ** Torsion, a type of

horse colic Colic in horses is defined as abdominal pain, but it is a clinical symptom rather than a diagnosis. The term colic can encompass all forms of gastrointestinal conditions which cause pain as well as other causes of abdominal pain not involving th ...

Gastric torsion Gastric dilatation volvulus (GDV), also known as gastric dilation, twisted stomach, or gastric torsion, is a medical condition that affects dogs and rarely cats and guinea pigs, in which the stomach becomes overstretched and rotated by excessive ...

, or gastric dilatation volvulus *

Torsion (gastropod) Torsion is a gastropod synapomorphy which occurs in all gastropods during larval development. Torsion is the rotation of the visceral mass, mantle, and shell 180˚ with respect to the head and foot of the gastropod. This rotation brings the mant ...

, a developmental feature of all gastropods

Mathematics

Torsion of a curve In the differential geometry of curves in three dimensions, the torsion of a curve measures how sharply it is twisting out of the osculating plane. Taken together, the curvature and the torsion of a space curve are analogous to the curvature o ...

Torsion tensor In differential geometry, the torsion tensor is a tensor that is associated to any affine connection. The torsion tensor is a bilinear map of two input vectors X,Y, that produces an output vector T(X,Y) representing the displacement within a t ...

, in differential geometry *

Torsion (algebra) In mathematics, specifically in ring theory, a torsion element is an element of a module that yields zero when multiplied by some non-zero-divisor of the ring. The torsion submodule of a module is the submodule formed by the torsion elements (i ...

, in ring theory *

Torsion group In group theory, a branch of mathematics, a torsion group or a periodic group is a group in which every element has finite order. The exponent of such a group, if it exists, is the least common multiple of the orders of the elements. For exam ...

, in group theory and arithmetic geometry *

Tor functor In mathematics, the Tor functors are the derived functors of the tensor product of modules over a ring. Along with the Ext functor, Tor is one of the central concepts of homological algebra, in which ideas from algebraic topology are used to const ...

, the derived functors of the tensor product of modules over a ring *

Torsion-free module In algebra, a torsion-free module is a module over a ring such that zero is the only element annihilated by a regular element (non zero-divisor) of the ring. In other words, a module is ''torsion free'' if its torsion submodule contains only t ...

, in algebra ** See also

Torsion-free (disambiguation) In mathematics, torsion-free may refer to: Abstract algebra * Torsion-free group, a group whose only element of finite order is the identity * Torsion-free module, module over an integral domain where zero is the only torsion element * Torsion-f ...

Analytic torsion In mathematics, Reidemeister torsion (or R-torsion, or Reidemeister–Franz torsion) is a topological invariant of manifolds introduced by Kurt Reidemeister for 3-manifolds and generalized to higher dimensions by and . Analytic torsion (or Ray– ...

(Reidemeister torsion, R-torsion, Franz torsion, de Rham torsion, Ray-Singer torsion), a topological invariant of manifolds *

Whitehead torsion In geometric topology, a field within mathematics, the obstruction to a homotopy equivalence f\colon X \to Y of finite CW-complexes being a simple homotopy equivalence is its Whitehead torsion \tau(f) which is an element in the Whitehead group \ope ...

, in geometric topology

Other uses

Torsion field (pseudoscience) A torsion field (also called axion field, spin field, spinor field, and microlepton field) is a reoccurring feature of many pseudoscience, pseudoscientific proposals. It posits that the Spin (physics), quantum spin of particles can be used to caus ...

, a field alleged to make faster-than-light communication and paranormal phenomena possible {{disambiguation, maths