The Abyss Nebula is a large gas cloud near an outer edge of the galaxy.

It was first surveyed in 2234 by the USS Byrd, and is composed primarily of interstellar dust. It was registered as "Stellar Catalog Beta 14-CN 625." It was standard information in the library computer of starships in the late 23rd century.

Some of the more important regions of the nebula are known as "Alpha CN625, Beta CN625, and Gamma CN625." (TOS video game: Star Trek: Starfleet Academy - Strategic Command)