Andúril is the name of Aragorn’s sword in The Lord of the Rings: The Return of the King.
Andúril is reforged from the shards of Narsil, the sword that Isildur used to cut the One Ring from Sauron’s hand. The reforging links Aragorn with his ancestor and confirms his claim to the throne of Gondor.
Elrond brings the newly reforged sword to Aragorn in the film. Aragorn then carries Andúril during the later stages of the War of the Ring, including the journey through the Paths of the Dead and the Battle of the Pelennor Fields.
The name Andúril means “Flame of the West” in Tolkien’s invented language Quenya. It is distinct from Glamdring, Gandalf’s sword; Sting, Bilbo and Frodo’s small blade; and Herugrim, King Théoden’s sword.