Any of the elementary particles that mediate one of the four fundamental forces. The particles and their corresponding forces are the photon and the electromagnetic force, the graviton and the gravitational force, the intermediate vector boson and the weak interaction, and the gluon and the strong interaction
Any of the three fundamental particles (the two W-bosons and the Z-boson) that transmit the weak nuclear force and have a mass about 100 times that of a proton