A nautical mile is a unit of measurement used in both air and marine navigation, and for the definition of territorial waters. Historically, it was defined as one minute (1/60 of a degree) of latitude along any line of longitude. Today the international nautical mile is defined as exactly 1,852 metres (1.1508 mi). The derived unit of speed is the knot, one nautical mile per hour.
There is no single internationally agreed symbol.