ETYM Cf. French annihilation.
1. Destruction by annihilating something; SYN. obliteration.
2. Total destruction; SYN. disintegration.
In nuclear physics, a process in which a particle and its “mirror image” particle called an antiparticle collide and disappear, with the creation of a burst of energy.
The energy created is equivalent to the mass of the colliding particles in accordance with the mass–energy equation. For example, an electron and a positron annihilate to produce a burst of high-energy X-rays.
Not all particle-antiparticle interactions result in annihilation; the exception concerns the group called mesons, which are composed of quarks and their antiquarks. See antimatter.