Nautical
Having to do with boats, ships or sailing.
Nautical mile
Distance at sea is measured in nautical miles, which are about 6,067.12 feet, 1.15 statute miles or exactly 1,852 meters. Nautical miles have the unique property that 1 minute of latitude is equal to 1 nautical mile. (There is a slight error, because the earth is not perfectly round.) Measurement of speed is done in knots, where 1 knot equals 1 nautical mile per hour. A statute mile is used to measure distances on land in the United States and is 5,280 feet.
Navigation
The act of determining the position of a boat and the course needed to safely move the boat from place to place.
Navigator
The person responsible for navigating a boat.