Definition:Nautical Mile

Definition
The nautical mile is a unit of length which is used for air and sea navigation.

It was originally defined as the length measured along Earth's surface of one minute of latitude along a meridian.

It is now defined as exactly $1852$ metres.

Also defined as
Before $1929$, the nautical mile was defined as either:
 * $6080$ feet (what is now known as the British admiralty mile)
 * $6080 \cdotp 2$ feet (the American nautical mile)

Older textbooks may still refer to either of these now obsolete units as the nautical mile.

Also see

 * Definition:Mile:
 * Definition:International Mile
 * Definition:Admiralty Mile