Tibor Nebula

The Tibor Nebula is a nebula located in Federation space between Betazed and the Argolis Cluster. 

In late-2374, the Starfleet Seventh Fleet engaged the Dominion near the nebula to attempt to prevent them from forming a supply line through Betazoid to the Argolis Cluster, which could be used to launch an attack against Vulcan. (: "A Magnificent View")