nautical mile
nautical mile. A measure of distance for air and sea navigation, equal to one minute of arc of a great circle of the earth. • Different measures have been used by different countries because the earth is not a perfect sphere. Since 1959, however, the United States has used an international measure for a nautical mile, set by the Hydrographic Bureau, equal to 6,076.11549 feet, or 1,852 meters.