Main Entry:

light–year

Pronunciation:

\ˈlīt-ˌyir\

Function:

noun

Date:

1888

1 : a unit of length in astronomy equal to the distance that light travels in one year in a vacuum or about 5.88 trillion miles (9.46 trillion kilometers) 2 : an extremely large measure of comparison (as of distance, time, or quality) <seems like light–years ago> <has light–years more talent> <two minutes and yet light–years away from the crowded village — Suzanne Patterson>