Subspace barrier

From Memory Alpha, the free Star Trek reference.

Subspace barrier is the term used of subspace when it acts as a barrier between two places.

An anti-time eruption was located inside a subspace barrier. A convergence of three inverse tachyon pulses from three different timeperiods ruptured the barrier and paradoxically created the anomaly. A new subspace barrier was generated artificially around the anomaly, with static warp shells, to collapse it. (TNG: "All Good Things...")

The long-range subspace warheads tested in the Subspace Munitions Range 434 were fired to their targets through subspace, and thus crossed a subspace barrier. When a warhead was closing in on the barrier, a minor gravimetric distortion was detectable near the exit point in the barrier. (VOY: "Human Error")