Which unit is similar in concept to a light-year?

The astronomical unit (AU) and the parsec are units similar in concept to a light-year. An astronomical unit is the average distance from Earth to the Sun, useful for measuring things within our solar system. A parsec is used for even larger astronomical distances; one parsec equals about 3.26 light-years. All of these units help astronomers describe and compare the vast distances in space without having to use very large numbers of kilometers or miles. They make calculations easier and give scientists a common language for discussing cosmic scales.​