Knot

A knot is a unit of speed equal to one nautical mile per hour, exactly 1.852 kilometers per hour.

Nautical mile: A unit of distance equal to 1,852 meters, approximately one minute of latitude. One nautical mile traveled in an hour defines one knot.
Nautical navigation: The planning and conduct of travel by water using position, direction, and distance. Ships report speed in knots alongside nautical miles and coordinates.
Chip log: A maritime device that estimates a vessel's speed by paying out a line with spaced knots. The unit's name comes from the knots counted on this traditional speed-measuring line.
Meters per second: A speed unit equal to one meter traveled per second. It is the SI speed unit, while a knot uses nautical miles per hour.
International System of Units: The internationally standardized system of measurement units, commonly abbreviated SI. SI provides the meters and seconds used to express knot speeds in standard units.
Aviation: The operation and technology of powered flight through Earth's atmosphere. Aircraft commonly express airspeed and wind speed in knots.
Log line: A marked line used at sea to measure a vessel's speed through the water. Its measured intervals gave sailors a practical basis for the knot.
Mach number: The ratio of an object's speed to the local speed of sound. Unlike a knot, it compares speed with a changing physical reference.
Kilometer per hour: A speed unit equal to the distance of one kilometer traveled in one hour. It measures the same quantity as knots but uses land-based distance units.
Air speed: The speed of an aircraft relative to the surrounding air. Knots express airspeed in aviation instruments and procedures.

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