… The usual enchantments… "Time to leave, Harry," said Dumbledore quietly, and as the in tie elf bobbed away bearing the boxes, Dumbledore grasped Harry once again above the elbow and together they rose up through oblivion and back to Dumbledore’s office.
There are no more uses of "oblivion" in the book.
Show samples from other sources
And if he kept his eye peeled quickly he would see himself, an instant before oblivion,
Ray Bradbury -- Fahrenheit 451
The ache inside Thomas was deep and gnawing, and he tried to sink further into oblivion.