Any mechanical (or other) system used to keep one or more variable parameters constant, or within specified bounds.

(physics) Of, or relating to statistical mechanics.

(physics) All of the physical laws of nature that account for the behaviour of the normal world, but break down when dealing with the very small (see quantum mechanics) or the very fast or very heavy (see relativity).

(physics) Early classical mechanics as propounded by Isaac Newton, especially that based on his laws of motion and theory of gravity.

(physics) The branch of physics which studies matter and energy at the level of atoms and other elementary particles, and substitutes probabilistic mechanisms in place of classical Newtonian ones.

The ratio of the output force produced by a machine (especially a simple machine) to the applied input force.

Referring to a period before the mechanization of farming or some other human activity.

(chemistry) the ordered set of individual reactions whose overall effect is given by a chemical equation

The branch of the modern military that is transported by light fast vehicles (including jeeps and helicopters), now serving the function historically provided by a horse cavalry.

(geology) a mechanical analogue of the seismic lithosphere, used to simulate the flexural deformations of the Earth