/ Dictionary / Index P proton synchrotron: Meaning and Definition of Find definitions for: pro'ton syn"chrotron Pronunciation: [key] — Physics. Physics. a synchrotron used for accelerating protons. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. proton-proton chain protopathic Related Content Daily Word Quiz: sumptuous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language