Discovery of the top quark, if confirmed, completes one set of subatomic building blocks whose existence is predicted by the prevailing theory, called the Standard Model, of the particles and forces that determine the fundamental nature of matter and energy. In the whimsical lexicon of modern physics, the elementary particles are called quarks, leptons and bosons.
Quarks, leptons, and bosons are the three elementary particles of physics according to the Standard Model.