Rigidity

Not to be confused with Rigor.

Rigid or rigidity may refer to:

Mathematics and physics

• Stiffness, the property of a solid body to resist deformation, which is sometimes referred to as rigidity
• Structural rigidity, a mathematical theory of the stiffness of ensembles of rigid objects connected by hinges
• Rigidity (electromagnetism), the resistance of a charged particle to deflection by a magnetic field
• Rigidity (mathematics), a property of a collection of mathematical objects (for instance sets or functions)
• Rigid body, in physics, a simplification of the concept of an object to allow for modelling
• Rigid transformation, in mathematics, a rigid transformation preserves distances between every pair of points
• Rigidity (chemistry), the tendency of a substance to retain/maintain their shape when subjected to outside force
• (Modulus of) rigidity or shear modulus (material science), the tendency of a substance to retain/maintain their shape when subjected to outside force

Medicine

• Rigidity (neurology), an increase in muscle tone leading to a resistance to passive movement throughout the range of motion
• Rigidity (psychology), an obstacle to problem solving which arises from over-dependence on prior experiences

Other uses

• Real rigidity, and nominal rigidity, the resistance of prices and wages to market changes in macroeconomics
• Ridgid, a brand of tools