/ Dictionary / Index O onyx marble: Meaning and Definition of Find definitions for: on'yx mar'ble Pronunciation: [key] See any compact, banded calcareous tufa that can be given a high polish. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. onyxis o-o Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language