Breadcrumb Home > Dictionary > Index O outermost: Meaning and Definition of Find definitions for: out•er•most Pronunciation: (ou'tur-mōst" or, esp. Brit., -must), [key] — adj. farthest out; remotest from the interior or center: the outermost limits. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: outermost (Thesaurus) Outer Mongolia outer planet ✖ Related Content Daily Word Quiz: triumphalism Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language