Definition that contains relativity theory
- event a phenomenon located at a single point in space-time; the fundamental observational entity in relativity theory
- dirac English theoretical physicist who applied relativity theory to quantum mechanics and predicted the existence of antimatter and the positron (1902-1984)
- mass-energy equivalence (physics) the principle that a measured quantity of mass is equivalent (according to relativity theory) to a measured quantity of energy
- eddington English astronomer remembered for his popular elucidation of relativity theory (1882-1944)
- paul adrien maurice dirac English theoretical physicist who applied relativity theory to quantum mechanics and predicted the existence of antimatter and the positron (1902-1984)
- sir arthur stanley eddington English astronomer remembered for his popular elucidation of relativity theory (1882-1944)
- cosmological constant an arbitrary constant in the equations of general relativity theory