/ Dictionary / Index R rock dust: Meaning and Definition of Find definitions for: rock' dust" Pronunciation: [key] a crushed limestone sprayed on surfaces in mines to make coal dust incombustible in case of a gas explosion. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. rock dove rock-eel Related Content Daily Word Quiz: arid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language