Related Clues:

• "In" place?
• Peephole's place
• Main way in
• It's implicit in knock-knock jokes
• Spot for a mail slot
• It may be French or Venetian
• Means of exit and entrance
• Moveable structure at an entrance
• One may perform or open it
• Cross it up and shut it up
• Open it and cross it up
• No way through the back
• Perform it or close it
• Cross up the way in
• Cross through it and cross back there