/ Dictionary / Index R reservoir rock: Meaning and Definition of Find definitions for: res'ervoir rock" Pronunciation: [key] — Geol. Geol. rock that has sufficient porosity to contain accumulations of oil or gas. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. reservoir reset Related Content Daily Word Quiz: nonchalant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language