Meaning

noun a track or mark left by something that has passed

noun a path or track roughly blazed through wild or hilly country

noun evidence pointing to a possible solution

originFrom Middle English trailen, from Old French trailler (“to tow; pick up the scent of a quarry”), from Vulgar Latin *tragulāre (“to drag”), from Latin tragula (“dragnet, javelin thrown by a strap”), probably related to Latin trahere (“to pull, drag along”).

Etymology from Wiktionary, CC BY-SA 3.0