Thinking of Gravity as a Wave
Remember that wave-partical duality thing? Just as electromagnetic radiation (light) and electrons can be thought of both as waves and particles, supposedly so could gravity. Just as a particle of light is called a photon, a particle of gravity is called a graviton. (Which could also be a wave)
The definition of a graviton is:
The messenger particle which carries the gravitational force. It plays a part in quantum gravity analogous to the
role of the photon in electromagnetic interactions described by QED. (From Q is for Quantum by John Gribbin)