Definition 1 of 2
Definition
The course measured in degrees from magnetic north, then corrected for the deviation error of the specific aircraft's magnetic compass. It is the heading you actually fly using the compass to track a desired course over the ground, after accounting for wind correction, magnetic variation, and compass deviation.
Plain English
The number of degrees you read on the compass when you are flying the path you want, after adjusting for everything that pulls the compass needle off true direction.
Context Anchor
Seen in magnetic compass error discussions, navigation planning, and any situation where a pilot converts a planned magnetic direction into what the cockpit compass should show.
Derivation
Compass' comes from the Latin 'com-' (together) and 'passus' (step or pace), originally meaning to measure out or mark a circle. 'Course' comes from the Latin 'cursus' meaning a run or path. Together: the path measured by the compass.
Why Pilots Care
Prevents navigation errors by compensating for the aircraft's own magnetic interference that would otherwise cause heading mistakes.
Intuition Check
Course does not mean a class or lesson here. In this context, it means the direction of the intended path, expressed in degrees.
Example Sentence 1
After applying variation and deviation to the true course, the pilot determined a compass course of 087 degrees.
Example Sentence 2
Preflight planning adjusted the compass course from the magnetic course to account for known deviation at that heading.