Definition
A unit of speed equal to one nautical mile per hour. One knot equals approximately 1.15 statute miles per hour or 1.852 kilometers per hour. Knots are the standard unit used in aviation to express airspeed, ground speed, and wind speed.
Plain English
A way of measuring speed used in flying and at sea. One knot means traveling one nautical mile in one hour. It is a little faster than one mile per hour as measured on a road.
Context Anchor
Seen on airspeed indicators, weather reports, wind reports, performance charts, and navigation planning.
Derivation
The term comes from old sailing ships, where speed was measured by tossing a rope into the water with knots tied at regular intervals. Sailors counted how many knots passed through their hands in a fixed time, and the count gave the ship's speed. Aviation inherited the unit from maritime navigation because both use nautical miles, which are based on the curvature of the Earth.
Why Pilots Care
All aircraft performance speeds, wind reports, and navigation calculations use knots, so using the wrong unit can lead to incorrect takeoff speeds or fuel planning.
Intuition Check
A knot does not mean a tied loop of rope here. In aviation, it means a speed unit: nautical miles per hour.
Example Sentence 1
The tower reported the wind from 270 at 15 knots, well within the aircraft's crosswind limit.
Example Sentence 2
The METAR reported surface winds at 15 knots gusting to 22 knots.