In J.R.R. Tolkien’s The Lord of the Rings, the word “mellon” comes from Sindarin and means “friend.” Gandalf uses it as the password at the Doors of Durin, the entrance to the Mines of Moria.
Sindarin is one of Tolkien’s principal Elvish languages. It was spoken primarily by the Sindar, or Grey Elves, and became a common Elven language in Middle-earth. Tolkien developed Sindarin with extensive attention to sound changes, grammar, and historical relationships to other Elvish tongues.
At the West-gate of Moria, the inscription instructs travelers to speak the password. The Fellowship initially interprets the message as a command to open the door, but Gandalf realizes that the answer is simply “friend.” Saying the word causes the doors to open.
A frequent confusion is between Sindarin and Quenya. Quenya is another major Elvish language, associated especially with the High Elves and often used in ceremonial or formal contexts. The Moria password is Sindarin, not Quenya.