Yes, trail is a Scrabble word!

Verb

1. To lag or linger behind

2. Go after with the intent to catch

3. Move, proceed, or walk draggingly or slowly

4. Hang down so as to drag along the ground

5. Drag loosely along a surface; allow to sweep the ground

Noun

1. A track or mark left by something that has passed

2. A path or track roughly blazed through wild or hilly country

3. Evidence pointing to a possible solution