A common term for the main gate of the Dwarf-citadel of Erebor.
Notes
1
Erebor originally had several gates around the Lonely Mountain, of which the Front Gate was the most important. After Smaug occupied Erebor in III 2770, he blocked all of these gates except the Front Gate, leaving that sole remaining entrance open for his own use. There was one other exception: the secret 'back door', unknown to the Dragon, used by Thorin and Company to enter the Lonely Mountain instead of using the main Front Gate.