e·ter·ni·ty
noun:
never-ending. It's
a relative term, meaning it is different for different people or situations.
Eternity is meant to explain a long period of time outside of that which we understand time to be. It's impossible to understand metaphysically because it has no beginning and no end.
So we humans understand eternity as it is in our everyday lives, like......
"I spent an eternity in line waiting for my
drivers license"
But in reality if one spent an eternity in line waiting you would know nothing but waiting in line from
your birth to your death, and nothing else, because it's an eternity with no start and no end.