Any of a class of elementary or composite particles, including the photon, pion, and gluon, that are not subject to the Pauli exclusion principle (that is, any two bosons can potentially be in the same
quantum state ). The value of the spin of a boson is always an integer. Mesons are bosons, as are the gauge bosons (the particles that mediate the fundamental forces). They are named after the physicist Satyendra Nath Bose. Compare
fermion. See Note at
elementary particle. See Table at
subatomic particle.