Related Clues:

• It may be between your teeth
• Pass between mountains
• It's beyond deep
• Intervening space
• Ravine formed by a river
• Nixon tapes problem
• It may be bridged
• Cumberland __
• Grand attraction
• Narrow ravine cut by a stream
• Wide difference
• Missing link
• Obvious space
• Unfathomable cavity, e.g.
• Gender ___