What is the name of the ring Bilbo finds in J.R.R. Tolkien’s The Hobbit?

The ring Bilbo finds in J.R.R. Tolkien’s The Hobbit is the One Ring.

Bilbo discovers the ring in the goblin tunnels beneath the Misty Mountains after becoming separated from Thorin’s company. He wins a riddle contest against Gollum and takes the ring without initially understanding its full significance. Its power to make its wearer invisible helps him escape.

In The Hobbit, the ring is presented mainly as a useful magical object. The Lord of the Rings later reveals that it is the One Ring, forged by Sauron in the fires of Mount Doom to control the other Rings of Power. Destroying it is essential to defeating Sauron.

The ring’s nature changed during Tolkien’s writing. Early versions treated it more like a mysterious invisibility ring, while the published sequel connected it to the central history of Middle-earth. The answer is therefore more specific than simply “an invisibility ring.”