Kos (unit)

The kos (Hindi: कोस), also spelled coss, koss, kosh, krosh, and krosha, is a unit of measurement which is derived from a Sanskrit term, क्रोश krośa, which means a 'call', as the unit was supposed to represent the distance at which another human could be heard. It is an ancient Indian subcontinental standard unit of distance, in use since at least 4 BCE. According to the Arthashastra, a krośa or kos is about 3,000 metres (9,800 ft).

Another conversion is based on the Mughal emperor Akbar, who standardized the unit to 5000 guz in the Ain-i-Akbari. The British in India standardized Akbar's guz to 33 inches (840 mm), making the kos approximately 4,191 metres (13,750 ft). Another conversion suggested a kos to be approximately 2 English miles.