| Normal strain: | (english) Strain measuring the intensity of deformation along an axis. Normal strain is usually denoted by . Average normal strain between two points is calculated as (Delta L / L), where L is the original distance between the points, and L is the change in that distance. Normal strain is often simply called strain. |
| Normal stress: | (english) Stress acting perpendicular to an imaginary plane cutting through an object. Normal stress has two senses: compression and tension. Normal stress is often simply called stress. |
| Pin connection: | (english) In two dimensions, a pin connection restrains two translation degrees of freedom but does not restrain rotation. Since the rotation degree of freedom is unrestrained at a pin connection, it transfers no moment. |
| Pin support: | (english) In two dimensions, a pin support restrains two translation degrees of freedom but does not restrain rotation. When considering reaction forces, a pin support is usually considered to have two force components: one each about the x and y axes respectively. |
| Pressure: | (english) Pressure is a similar idea to stress, the force intensity at a point, except that pressure means something acting on the surface of an object rather than within the material of the object. When discussing the pressure within a fluid, the meaning is equivalent to stress. |
| Reaction: | (english) A reaction is a force exerted by a support on an object: sometimes called support reaction. Using this definition, a reaction is an external force. |
| Resultant: | (english) The resultant of a system of forces is a single force or moment whose magnitude, direction, and location make it statically equivalent to the system of forces. |
| Roller support: | (english) In two dimensions, a roller support restrains one translation degree of freedom. |
| Shear strain: | (english) Strain measuring the intensity of racking in the material. Shear strain is measured as the change in angle of the corners of a small square of material. |
| Stability: | (english) Stability is best defined as the opposite of instability, which is the occurrence of large structural deformations which are not the result of material failure. |