Bosons

Bosons are particles that obey Bose-Einstein statistics. Bosons make up one of the two families of subatomic particles, the other being fermions. The name "Boson" was coined by Paul Dirac. This was to commemorate the contribution of Satyendra Nath Bose, who along with Albert Einstein, developed the Bose-Einstein statistics. 

Examples of bosons are the fundamental particles such as the photon, gluon and W and Z boson. These are the 4 force carriers described by the Standard Model of particle physics. There is also the recently discovered Higgs boson and the hypothetical graviton of theories of quantum gravity. There are also some composite particles that are also bosons, such as mesons. 

An important feature of bosons is that there is no restriction on the number of them that can occupy the same quantum state.