Baryon

Baryons are composite subatomic particles. They contain an odd number of quarks (at least 3.) Baryons are hadrons. Hadrons are composed of quarks. Baryons are also classified as fermions, since they have a half-integer spin. 

Baryons were named by Abraham Pais. It comes from the Greek word for "heavy," since when baryons were so named, they were more massive than most known elementary particles. Each baryon has a corresponding antiparticle or antibaryon. The corresponding antiquarks will replace the quarks. For example, a proton is composed of 2 up quarks and 1 down quark. An antiproton, by the same token, is composed of 2 up antiquarks and 1 down antiquark. 

Baryons are composed of quarks, thus, they participate in the strong nuclear interaction. This is mediate by particles known as gluons. The most familiar of the baryons are the protons and the neutrons. Protons and neutrons both contain 3 quarks. They are sometimes known as "triquarks" for this reason.