/ Dictionary / Index A atomic pile: Meaning and Definition of Find definitions for: atom'ic pile' Pronunciation: [key] — Physics. Physics. reactor (def. 4). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. atomic orbital atomic power Related Content Daily Word Quiz: crutiny Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language