/ Dictionary / Index O optical path: Meaning and Definition of Find definitions for: op'tical path' Pronunciation: [key] the path of light through a medium, having a magnitude equal to the geometric distance through the system times the index of refraction of the medium. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. optical maser optical printer Related Content Daily Word Quiz: loathe Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language