annihilation

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act or process of annihilating.
• noun The condition of having been annihilated; utter destruction.
• noun Physics The phenomenon in which a particle and an antiparticle, such as an electron and a positron, meet and are converted to a combination of energy or energetic particles approximately equivalent to the sum of their masses.

from The Century Dictionary.

• noun The act of annihilating or of reducing to nothing or non-existence, or the state of being reduced to nothing.
• noun The act of destroying the form of a thing or the combination of parts which constitute it, or the state of being so destroyed: as, the annihilation of a corporation.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of reducing to nothing, or nonexistence; or 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.
• noun The state of being annihilated.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The act of reducing to nothing, or nonexistence; or 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; as, the annihilation of a corporation.
• noun The state of being annihilated.
• noun physics The process of a particle and its corresponding antiparticle combining to produce energy.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun total destruction
• noun destruction by annihilating something