Doors of Durin

The enchanted doors that guarded the western entrance to Khazad-dûm. They were made by Narvi in the Second Age, and Celebrimbor himself traced signs on the doors in ithildin. The gateway would normally stand open during the years of friendship between Khazad-dûm and Celebrimbor's people in Eregion, to the west. When they were closed they could be opened again by speaking a single word, 'mellon' - the Elvish for 'friend'.