Light Year: A light year is the distance that light travels in one year through a vacuum, approximately equal to 9.461 trillion kilometers (about 5.878 trillion miles). It's used to measure vast cosmic distances.
A "nail" is a traditional unit of length used for measuring cloth or fabric, particularly in some regions of India. The nail is based on the width of a finger, and it is typically equal to approximately 2.25 inches or about 5.715 centimeters.
Nails were historically used in the textile and clothing industry to measure the width of cloth or fabric. However, like many other traditional units of measurement for textiles, the nail has largely been replaced by more standardized and metric units, such as inches, centimeters, or meters, in modern times.