Light year (ly)
Definition: Light year (symbol: ly) na the distance wey light travel for vacuum for one Julian year, wey equal about 9.4607 trillion kilometers or 9.4607 × 10^15 meters.
History/origin: Astronomers adopt light year as practical way to talk about huge interstellar distances wey go need very big numbers if na kilometers or miles.
Current use: Light years dey mainly for astronomy and science communication to describe distances between stars, nebulae, and other objects outside our solar system.