Eternal means lasting forever, with no beginning or end, or continuing for so long that it seems endless. When something is eternal, time cannot touch it or wear it down.

Many religions describe God as eternal, existing before time began and continuing after time ends. Ancient philosophers wondered about eternal truths, like mathematical principles that would remain true even if the universe disappeared. The night sky, filled with stars that have shone for billions of years, can feel eternal even though we know stars eventually burn out.

Sometimes people use eternal to describe things that feel like they last forever, even if they technically don't. Waiting in a very long line might feel like an eternity, though it's really just an hour. A boring lecture can seem eternally long. The eternal snows of Antarctica have actually been there for millions of years, which is about as close to forever as most things get.

The opposite of eternal is temporary or fleeting. A rainbow is beautiful but temporary; a diamond, people say, is forever. When something matters so deeply that you cannot imagine it ever ending, like the love in a strong family, you might call it eternal. The word captures that feeling of permanence, of something so solid and lasting that time itself cannot change it.