/ Dictionary / Index P protest flag: Meaning and Definition of Find definitions for: pro'test flag" Pronunciation: [key] a flag hoisted by a racing yacht to advise the judges of a violation of the rules by another yacht. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. protestation protest vote Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language