Trail means to follow behind someone or something, often at a distance or more slowly. In a race, if you're trailing the leader, you're running behind them, trying to catch up. A detective might trail a suspect through the city, staying far enough back to avoid being noticed. When your little brother trails after you around the house, he's following wherever you go, perhaps hoping to join in whatever you're doing.

The word can also describe something that drags or hangs down behind. A wedding dress might have a long train of fabric that flows across the floor. When a plane flies high in the sky, it sometimes leaves a white vapor trail streaming behind it.

A trail (as a noun) is a path through wilderness or natural areas, marked so hikers can find their way. The Appalachian Trail stretches over 2,000 miles through the eastern United States. Trails can be narrow dirt paths through forests, rocky routes up mountains, or wider paths through parks. Native Americans and early explorers created many trails that people still use today. When you blaze a trail, you're creating a new path where none existed before, marking trees or rocks so others can follow. This phrase also means being the first to try something new or difficult.