A mythical end of the world, uncertain when it is going to happen, several sects disagree about it:

Jehovah's Witnesses - When Jesus makes a second coming.
Donald Trump supporters - When Hillary Clinton becomes President of the United States.
Hillary Clinton supporters - When Donald Trump becomes President of the United States.

An Apocalypse (Greek: Apokálypsis; "lifting of the veil" or "revelation") is a disclosure of something hidden from the majority of mankind in an era dominated by falsehood and misconception, the lifting of the veil. Illumination.

An apocalypse is the end of the world as we know it. Everything and everyone will die, and there will be no more planet Earth.

the day that george bush gets reelected, so i guess the apocalypse has already happened

Something that will never happen while all of us are alive.

The end of the world. See also apoopalypse

1. When the retarded and pathetic efforts set forth by humanity are ended.