Why is the distance between stars expressed in light years? What do you understand by the statement that a star is eight light years away from the earth?

Explanation

The distance of stars is so large that it cannot be expressed in terms of kilometer. That is why very large distances are expressed in another unit known as light year. One light year is the distance travelled by light in one year.
If the distance of a star is eight light years, it means that this distance is the distance travelled by light in eight years.