ˈlight year noun [countable]

1. the distance that light travels in one year, about 9,460,000,000,000 kilometres, used for measuring distances between stars:
a star 3,000 light years from Earth

2. light years ahead/better etc than something informal much more advanced, much better etc than someone or something else:
The Japanese company is light years ahead of its European competitors.

3. light years ago informal a very long time ago:
It all seems light years ago now.

[TahlilGaran] Dictionary of Contemporary English ▲