| Noun | 1. | theory of gravity - (physics) the theory that any two particles of matter attract one another with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between themlaw of gravitation, Newton's law of gravitation - (physics) the law that states any two bodies attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them scientific theory - a theory that explains scientific observations; "scientific theories must be falsifiable" | |