Quark- A quark is a subatomic particle which makes up protons, neutrons and other particles classified as baryons and mesons. Baryons and mesons form a family referred to as hadrons. There are 6 different quarks: up, down, top, bottom, charm, and strange. Each quark also has an associated "antiquark" which has all of the same properties except some have the opposite sign, i.e. charge, spin, etc. Baryons are particles made of 3 quarks and mesons are made of 2 quarks. Protons and Neutrons are both Baryons. A proton is made of two up quarks and a down quark. A Neutron is made of two down quarks and an up quark.
