(physics) The mechanics of objects moving at velocities comparable to the speed of light; is compatible with the special and general theories of relativity.

(physics) The study of the motion of individual particles.

The science that studies the mechanical behaviour of rock.

(physics, mathematics) The mathematical basis for quantum mechanics in which light and subatomic particles have the characteristics of both waves and particles.

(mechanics) The branch of mechanics dealing with gases and liquids, either at rest or in motion.

The application of mechanics (especially fluid mechanics) to soils, especially as a basis for the design and construction of building foundations and earthworks.

(astronomy) The dynamics of celestial bodies subject to mutual gravitational attraction.

(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.