c.1300, "to hang down loosely and flow behind," from Old French trailler "to tow," ultimately from Vulgar Latin *tragulare "to drag," from Latin tragula "dragnet," probably related to trahere "to pull" (see tract (n.1)). The meaning "follow the trail of" (an animal, etc.) is first recorded late 14c. Related: Trailed; trailing.
early 14c., "trailing part of a robe, gown, etc.," from the source of trail (v.). The meaning "track or smell left by a person or animal" is also from 1580s. Meaning "path or track worn in wilderness" is attested from 1807.