Definition
A unit of speed equal to one nautical mile per hour. One knot is approximately 1.15 statute miles per hour or 1.852 kilometers per hour. Knots are the standard unit for measuring airspeed, ground speed, and wind speed in aviation.
Plain English
A way to measure speed used in flying and at sea. One knot means you are covering one nautical mile every hour. It is a little faster than one mile per hour on the road.
Context Anchor
Pilots see knots on airspeed indicators, weather reports, performance charts, and air traffic control information.
Derivation
The term comes from old sailing ships. Sailors measured speed by tossing a rope into the water with knots tied at regular intervals. They counted how many knots passed through their hands in a set time, and that number became the ship's speed. Aviation borrowed the unit because flying, like sailing, uses nautical miles based on the size of the Earth.
Why Pilots Care
Aircraft performance numbers, true airspeed, groundspeed, and wind calculations are all stated in knots so they align directly with nautical-mile navigation charts and distances.
Intuition Check
Knots are not tied loops here; they are a speed unit. Also, a knot already means “per hour,” so saying “knots per hour” is usually incorrect when you mean speed.
Example Sentence 1
The tower reported the wind as 270 at 15 knots, giving us a steady headwind on final.
Example Sentence 2
The reported wind was 12 knots gusting to 18 knots from the northwest.