A light year is a way of measuring distance. That doesn't make much sense because "light year" contains the word "year," which is normally a unit oftime. Even so, light years measure distance.
You are used to measuring distances in either inches/feet/miles or centimeters/meters/kilometers, depending on where you live. You know how long a foot or a meter is -- you are comfortable with these units because you use them every day. Same thing with miles and kilometers -- these are nice, human increments of distance.
When astronomers use their telescopes to look atstars, things are different. The