What is the name for the opposite of an "event horizon?"?

Question

I once read that white-holes have horizons that can't ever be reached, or the opposite of an event horizon found around black holes. What is the name for this type of horizon?

Answer 1

It's possible that there could be such things as 'white holes', the opposite of black holes, spewing out matter and energy into the Universe. However, this is just another of the cosmic mysteries still awaiting a solution.

Answer 2

Same name.  Event horizon.  Except with a white hole, you would inevitably cross it from the "inside."