quantum system invariant by exchange of two identical instances

A boson is a particle which carries a force. It has a whole number spin (spin is a property of subatomic particles). Bosons carry energy.

A photon is an example of a boson as it has a spin of 1 and carries electromagnetism. Mesons are also bosons as they carry nuclear force.

Bosons are different from fermions, which are particles that make up matter, because bosons obey Bose-Einstein statistics. (This means that you can put two of them in the same place at the same time; the Pauli exclusion principle does not apply.)

Gauge bosons carry fundamental forces. There are three known gauge bosons, which are elementary particles. For example, the photon carries the electromagnetic force. The three types of gauge bosons are: photons for electromagnetism, gluons (eight kinds) for strong force, and W and Z bosons (three kinds) for weak force. Other theoretical gauge bosons are predicted, such as gravitons for gravity. The Higgs boson is another fundamental particle of a type called a scalar boson.

Paul Dirac named this class of particles "bosons" in honour of a famous Indian scientist called Satyendra Nath Bose.

The theory related to boson was given by S.N.Bose (An Indian Physicist). He worked along with einstien to give the famous theory about bosons which are the particles which carry force and energy along with them.