/ Dictionary / Index O optimal: Meaning and Definition of Find definitions for: op•ti•mal Pronunciation: (op'tu-mul), [key] — adj. optimum (def. 3). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: optimal (Thesaurus) optics optime Related Content Daily Word Quiz: ontiguous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language