/ Dictionary / Index U undersaturated: Meaning and Definition of Find definitions for: un•der•sat•u•rat•ed Pronunciation: (un"dur-sach'u-rā"tid), [key] — adj. Chem. unsaturated (def. 2). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. underrun underscore Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language