In particle physics, a boson is a type of particle that obeys the rules of Bose-Einstein statistics. These bosons also have a quantum spin with contains an integer value, such as 0, 1, -1, -2, 2, etc. (By comparison, there are other types of particles, called fermions, that have a half-integer spin, such as 1/2, -1/2, -3/2, and so on.)
Bosons are sometimes called force particles because they control the interaction of physical forces, such as electromagnetism and possibly even gravity itself.