/ Dictionary / Index O obsolesc.: Meaning and Definition of Find definitions for: obsolesc. Pronunciation: [key] obsolescent. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. obsidional coin obsolesce Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language