Airspeed Indicator.svg
An airspeed indicator, which shows speed in knots
General information
Unit system
  • meteorology
  • aviation
  • maritime
Unit ofspeed
Symbolkn or kt 
1 kn in ...... is equal to ...
   km/h   1.852
   mph   1.15078
   m/s   0.514444
   ft/s   1.68781

The knot (/nɒt/) is a unit of speed equal to one nautical mile per hour, exactly 1.852 km/h (approximately 1.15078 mph or 0.514 m/s).[1] The ISO standard symbol for the knot is kn.[2] The same symbol is preferred by the Institute of Electrical and Electronics Engineers (IEEE); kt is also common, especially in aviation, where it is the form recommended by the International Civil Aviation Organization (ICAO).[3] The knot is a non-SI unit.[4] The knot is used in meteorology, and in maritime and air navigation. A vessel travelling at 1 knot along a meridian travels approximately one minute of geographic latitude in one hour.

Etymologically, the term derives from counting the number of knots in the line that unspooled from the reel of a chip log in a specific time.