Plain English Meaning
A nautical mile is a measurement of distance used by pilots and sailors. It is a bit longer than the regular mile used on roads -- about 15% longer. It is used in flying because it matches up neatly with lines on a navigation chart.
Full Definition
A unit of distance used in aviation and marine navigation, equal to 6,076 feet, or approximately 1.15 statute miles, or 1,852 meters. One nautical mile corresponds to one minute of latitude along any meridian on the Earth's surface.
Context Anchor
You will see nautical miles in flight planning, navigation, chart distances, wind correction, and discussions of ground track.
Derivation
From the Latin 'nauticus' meaning 'of ships,' which traces back to the Greek 'nautes' meaning 'sailor.' The unit originated at sea, where distances were tied directly to the Earth's geometry rather than to land-based units, and aviation inherited it because and navigation use the same .