Boson is the general name for any particle with a spin of an integer number ( 0, 1, 2, ...) of quantum units of angular momentum. Bosons, named by Paul Dirac in 1947 after the Indian physicist Satyendra Nath Bose, are the carrier particles of all fundamental interactions. Mesons and photons are also bosons. Mesons have spin 0, photons spin 1, and the as yet-undetected graviton, associated with the gravitational force between masses, spin 2.
Bosons do not obey the Pauli exclusion principle. This means there is no limit to the number of bosons that can occupy the same point in space at the same time; so, for example, there is no limit in theory to the brightness of a beam of light. Compare with fermion.