Docking bay refers to a specific area within a spacedock where a starship or other space-going vessel can dock for maintenance, supplies or shore leave. In larger space stations, docking bays can be enclosed within their primary hull, or other structure, accessible through space doors.
Watchtower-class space stations, such as Vanguard, had four docking bays within their primary hulls. Each bay was large enough to accommodate a Constitution-class starship. (VAN novels: Harbinger, Open Secrets; Star Trek Magazine Issue 162: "Blast Off!")