/ Dictionary / Index R rock milk: Meaning and Definition of Find definitions for: rock' milk" Pronunciation: [key] a white, powdery surface crust of calcite, formed by efflorescence in limestone caves and fissures. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. rock maple Rockne Related Content Daily Word Quiz: entomology Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language