Definition: Antinucleon is a term in physics that refers to an anti-quark, which does not have a nucleonic particle. It's often used to describe particles with properties similar to the electron but without the electron's electric charge, like the antiparticle of the proton. Definition: An antinucleon (anti-positron) is a particle with properties analogous to that of the positively charged electron but lacking the ability to donate an electron. Antimatter, as in antiprotons and antineutrons, are particles that have no mass or charge and therefore cannot be observed by conventional experiments. Antiparticle: An antiparticle is a particle that has opposite electric charges than its original counterpart. For example, electrons have two electric charges, while protons only carry one. Antimatter particles lack these electric charges, making them indistinguishable from each other.