The ring forged by Sauron in J.R.R. Tolkien’s The Lord of the Rings is called the One Ring.
Sauron created it in the fires of Mount Doom during the Second Age. He placed much of his power into it so that he could control the other Rings of Power and dominate their bearers. The inscription on the Ring is written in the Black Speech of Mordor and appears when the Ring is heated.
The One Ring is not one of the three Elven Rings, which are named Narya, Nenya, and Vilya. Those three were made by Elves, although Sauron’s broader ring-making scheme affected their history. This is a frequent source of confusion because all are Rings of Power.
In The Lord of the Rings, destroying the One Ring is essential to defeating Sauron. It can be unmade only in the fire of Mount Doom, where it was forged. The quest therefore links the Ring’s origin, power, and destruction to the same volcanic location.