/ Dictionary / Index L leading mark: Meaning and Definition of Find definitions for: lead'ing mark" Pronunciation: (lē'ding), [key] — Navig. Navig. either of two conspicuous objects regarded as points on a line upon which a vessel can sail a safe course. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. leading man leading question 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