An Etymological Dictionary of Astronomy and Astrophysics

The process in which the entire → mass of → two colliding → particles, one of → matter and one of → antimatter, is → converted into → radiant energy in the form of → gamma rays. See also → annihilation operator.

Etymology (EN): L. annihilatus, p.p. of annihilare “to reduce to nothing,” from ad- “to” + nihil “nothing,” from ne- “not” + hilum “small thing, trifle”

Etymology (PE): Nâbudi, from nâ- “not” + bud “to be, exist,” from budan “to be, exist” + -i noun forming suffix.