Spin Spin Spin is the name for the angular momentum carried by a particle. For composite particles, the spin is made up from the combination of the spins of the constituents plus the angular momentum of their motion around one-another. For fundamental particles spin is an intrinsic and inherently quantum property, it cannot be understood in terms of motions internal to the object. The intrinsic spin must be included in applications of conservation of angular momentum. Fermions and Bosons Particles can be divided into two classes on the basis of their spins.
Bosons are particles with integer spin in h-bar units.
You may be familiar with this type of rule for electrons in atoms. Bosons do not follow such a rule and, in a certain sense, favor states with many particles in the same state. Baryons are made from odd numbers of quarks and so are fermions. Mesons also are bosons.