Time that never ends, or a state beyond time as we normally experience it. People also use it informally to mean a very long time.
From Latin *aeternitas* 'eternity', from *aeternus* 'everlasting'. It has been important in religious discussions about the soul and the afterlife.
Eternity turns time into something almost like a place you could enter, not just a line you move along. We shrink it in everyday talk—'this class is taking an eternity'—because true endlessness is hard to grasp. The word lets us complain about boredom and dream about immortality with the same syllables.
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