classical physics

American  

[klas-ik-uhl fiz-iks] / ˈklæs ɪk əl ˈfɪz ɪks /

noun

1. physics as understood before the advent of quantum mechanics and the theory of relativity, or those aspects of contemporary physics that do not involve or rely on these theories.

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classical physics Scientific  

1. Physics that does not make use of quantum mechanics or the theory of relativity. Newtonian mechanics, thermodynamics, and Maxwell's theory of electromagnetism are all examples of classical physics. Many theories in classical physics break down when applied to extremely small objects such as atoms or to objects moving near the speed of light.

2. ◆ Classical mechanics refers to the classical physics of bodies and forces, especially Newton's laws of motion and the principles of mechanics based on them.

3. Compare quantum mechanics

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Other Word Forms

• classical physicist noun
• classical-physics adjective

Example Sentences

The knots ultimately unraveled through quantum tunneling, a process in which particles cross energy barriers that would be insurmountable in classical physics, as if they were passing through a wall.

From Science Daily • Dec. 7, 2025

This uniquely quantum phenomenon cannot be explained by the laws of classical physics, yet it is one of the properties that explains the macroscopic behavior of quantum systems.

From Science Daily • Apr. 24, 2024

She finds as much joy in defying classical physics on the mountain in Aspen as exploring quantum physics in the classroom at Stanford.

From Seattle Times • Jan. 27, 2024

A system that is well above this temperature will largely behave according to the laws of classical physics; if it is well below, its behavior will be ruled by quantum mechanics.

From Scientific American • Jul. 18, 2023

So at first there was not one Scientific Revolution but two, one exemplified by Newton’s classical physics, the other by Rutherford’s nuclear physics.

From "The Invention of Science" by David Wootton