Oblivion

Final Fantasy 10
Oblivion is the Overdrive for the Aeon Anima from Final Fantasy 10. It is a devastating attack that will probally be the first of your attacks to reach 99,999 damage. It starts with Anima sending the Opponent underground, and then its lower half breaks its bonds and unleashes hell on the enemy.

Kingdom Hearts 1 & 2
Oblivion is one of the best Keyblades for Sora in Kingdom Hearts. It is always found in a chest near the end of the game. It is a black sword with a chain design built into the handle. It also has a black crown as its Keychain

Kingdom Hearts: Chain of Memories
Oblivion is still a Keyblade, but it is also the castle in which the entire game takes place. It is an enormous castle in a green field. It is massive, and those who enter have their memories tampered with by Namine.

The Literal Meaning
It is supposed to be a place of nothingness, said by some where all things eventually end up. It is always used as a term of desruction and commonly used in threats.