/ Dictionary / Index L line of sight: Meaning and Definition of Find definitions for: line' of sight' Pronunciation: [key] Also calledan imaginary straight line running through the aligned sights of a firearm, surveying equipment, etc. an imaginary line from an observer to a celestial body, coincident with the path traveled by light rays receivedfrom the body. a straight line connecting two points sufficiently high and near one another so that the line is entirely above the surface of the earth. See sightline. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. line of scrimmage line of site Related Content Daily Word Quiz: lunar Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language