/ Dictionary / Index R rocking valve: Meaning and Definition of Find definitions for: rock'ing valve" Pronunciation: [key] (on a steam engine) a valve mechanism oscillating through an arc to open and close. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. rocking stone Rock Island Related Content Daily Word Quiz: morose Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language