/ Dictionary / Index P particle accelerator: Meaning and Definition of Find definitions for: par'ticle accel"erator Pronunciation: [key] accelerator (def. 7). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. particle particle beam Related Content Daily Word Quiz: fervor Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language