Molecular motion is the movement of atoms or molecules that compose a substance. It is an essential element in various chemical and biological processes. There are several synonyms for the term molecular motion, including thermal motion, kinetic energy, Brownian motion, and random motion. Thermal motion refers to the energy that results from the temperature of a substance, which fuels the movement of its molecules. Kinetic energy, on the other hand, refers to the energy that a substance possesses due to its motion. Brownian motion is the erratic movement of small particles in a fluid, caused by the collision of molecules. Random motion is a term used to describe any movement that is not directional or predictable.