A plug door is a door designed to seal itself by taking advantage of pressure difference on its two sides and is typically used on aircraft with cabin pressurization. The higher pressure on one side forces the wedge-shaped door into its socket, making a good seal and preventing it being opened until the pressure is released.
Non-plug doors rely on the strength of the locking mechanism to keep the door shut whereas a plug door relies on the pressure differential to keep it shut.
The term "plug door" may also refer to a sliding bus door that is not actually held in place by pressure, but is mechanically wedged into place when closed.
Read more about Plug Door: Pressure-sealed Plug Doors, Other Plug Doors
Famous quotes containing the word door:
“The door is opening. A man you have never seen enters the room.
He tells you that it is time to go, but that you may stay,
If you wish. You reply that it is one and the same to you.
It was only later, after the house had materialized elsewhere,
That you remembered you forgot to ask him what form the change would take.”
—John Ashbery (b. 1927)