Interspatial manifolds
An interspatial manifold was an advanced technology used by races such as the Sphere Builders and the Borg.
The Delphic Expanse spheres each contained an interpatial manifold, used for gravimetrically linking all of the spheres to create the Expanse. (ENT: "Countdown")
The Borg used interspatial to support the structure of a transwarp hub. The manifolds were protected by force fields, which were controlled by the Borg Queen and were essential for the operation of a transwarp hub.
If one of the manifolds was destroyed, the hub could still function. If enough of them could be destroyed simultaneously, a cascade reaction would occur which would then lead to the destruction of the transwarp hub. (VOY: "Endgame")