The Unending Ocean is the name used for the ocean(s) of the world. It is unclear if Tyrians consider it one ocean or many with the same name, but all large bodies of water are called the Unending Ocean.
The island chain known as the Battle Isles resides within the Unending Ocean, specifically within the Clashing Seas, between the three continents. In ancient days before the Exodus of the Gods and the distribution of magic, the Margonites were said to rule the Unending Ocean before they lost their humanity.
The Krait are known to live on the ocean floor of the Unending Ocean.