1.nounThe state of forgetting completely, of being oblivious, unconscious, unaware, as when sleeping, drunk, or dead.
"He regularly drank himself into oblivion."
2.nounThe state of being completely forgotten, of being reduced to a state of non-existence, extinction, or nothingness, incl. through war and destruction. (Figuratively) for an area like hell, a wasteland.
"Due to modern technology, many more people and much more information will not slip into oblivion, contrary to what happened throughout history until now."