ground zero: Meaning and Definition of

ground' ze'ro

Pronunciation: [key]
  1. the point on the surface of the earth or water directly below, directly above, or at which an atomic or hydrogen bomb explodes.
  2. the very beginning or most elementary level: Some of the students are starting from ground zero.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.