Plain English Meaning
The direction you plan to fly, expressed as a compass number and shown as a line on the map between where you started and where you are going.
Full Definition
The intended horizontal direction of travel of an aircraft, measured in degrees from north (true, magnetic, or grid), and usually drawn as a line on a chart from the point of departure to the destination.
Context Anchor
You will see course in navigation, flight planning, and when following a selected path on a chart or cockpit display.
Derivation
From the Latin 'cursus,' meaning 'a running' or 'path traveled.' In navigation it kept this sense of a planned path — the line you intend to follow across the ground.
Why Pilots Care
Maintaining the correct course keeps the aircraft on the planned , avoids , and ensures at the destination.