annihilation

Short definition from Wiktionary

Noun

1. 1
   The act of destroying or otherwise turning into nothing, or nonexistence.
2. 2
   The act of destroying the form or combination of parts under which a thing exists, so that the name can no longer be applied to it.
3. 3
   The state of being annihilated.
4. 4
   The process of a particle and its corresponding antiparticle combining to produce energy.