Mellon is the Elvish word meaning “friend” in J.R.R. Tolkien’s inscription at the Doors of Durin.
The Doors of Durin stand at the western entrance to Moria, also called Khazad-dûm. The inscription says, in translation, “Speak, friend, and enter.” Gandalf initially interprets the instruction as a request for a password, but he eventually realizes that saying the Elvish word mellon opens the doors.
The word comes from Sindarin, one of Tolkien’s developed Elvish languages. The scene illustrates how language is part of the plot rather than merely decoration: the travellers are not required to know a secret invented phrase, but to understand the meaning of the inscription.
The doors were made by the Dwarves of Moria and designed by the Elf Celebrimbor. Their imagery combines Dwarvish construction with Elvish lettering and symbols, reflecting the historical friendship between Durin’s folk and the Elves of Eregion.