Galilean relativity refers to the concept of how physical laws remain the same for all observers moving at a constant velocity. The idea was first proposed by Galileo Galilei in the 17th century and was later expanded upon by Sir Isaac Newton. Synonyms for Galilean relativity include Galilean invariance, Galilean transformation, Galilean principle of relativity, and Galilean spacetime. Other related concepts include Special Relativity, which focuses on the behavior of objects moving at near the speed of light, and General Relativity, which deals with the curvature of spacetime caused by massive objects. These ideas revolutionized the field of physics and laid the foundation for modern theories such as quantum mechanics and string theory.