/ Dictionary / Index O onyx: Meaning and Definition of Find definitions for: on•yx Pronunciation: (on'iks, ō'niks), [key] — n. a variety of chalcedony having straight parallel bands of alternating colors. Cf. (not used technically) an unbanded chalcedony dyed for ornamental purposes. black, esp. a pure or jet black. a nail of a finger or toe. —adj. black, esp. jet black. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: onyx (Thesaurus) -onym onyxis Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language