Antimatter is matter composed of elementary particles that are the opposite of ordinary particles. These opposite particles are called antiparticles. An antiparticle that carries an electric charge resembles its corresponding ordinary particle in every property except its charge, which is reversed. For example, an electron is an ordinary particle that has a negative electric charge. Its antiparticle, a positron, exactly resembles it except that a positron carries a positive electric charge. A neutrino, which carries no charge, has an antimatter counterpart called an antineutrino, which differs from the neutrino in the direction of its spin (see Neutrino).