Related Clues:

• It might become unhinged
• It can open (and close!)
• Advent calendar flap
• Thing you open
• Root location
• Visit either partner's house
• Head covered by hair
• Next-___ neighbor
• Keyhole's place
• Word before "trap" and "bell"
• It opens and closes
• Place for a knob
• Way in — way out
• Where bald people might get sunburned
• Unit in the Monty Hall problem