Subatomic particle

Hadrons are particles composed of quarks. They inlcude baryons and mesons, which are described below.

Baryons are composed of three quarks, usually of the Up or Down variety. They all have a very large rest mass for subatomic particles. Types of Baryons (Proton, Neutron)

Mesons are composed of a normal quark, and an antiquark, which causes the Baryon number to go to zero. None of these are very stable, but have half lives on the order of nanoseconds. They have a decent rest mass too. Types of Mesons (Pion)

Leptons contain no quarks, but are small singular particles in themselves. Some have no rest mass, while others have very large rest mass. Types of Leptons (Electron, Muon, Tauon[?], neutrino)

For More Information, go to Particle Physics, boson, fermion, fundamental particle.