Dirac particles are a class of particles that obey the principles of quantum mechanics and relativistic quantum field theory. They are named after the physicist Paul Dirac, who formulated a theory that combined quantum mechanics with special relativity. Dirac particles include fermions, which are particles that follow the Pauli exclusion principle and have half-integer spin, such as electrons and quarks. These particles are significant because they account for the behavior of matter at the smallest scales. Dirac's equations predicted the existence of antimatter, leading to the discovery of positrons, the antimatter counterparts of electrons. This groundbreaking work has had profound implications for our understanding of the universe.