Definition
A movable pointer or marker on a horizontal situation indicator (HSI) or similar navigation display that the pilot rotates to set the desired course (selected radial or track) to or from a navigation station. Once set, the course arrow shows the orientation of that course relative to the aircraft's heading.
Plain English
An arrow on the navigation instrument that the pilot turns to point along the path they want to fly. After it is set, it shows where that path lies compared to where the aircraft is currently pointed.
Context Anchor
Seen on navigation and performance instrument displays when a pilot selects a course to track or intercept.
Derivation
Course comes from the Latin cursus, meaning a running, path, or direction of travel. That helps here because the course arrow marks the chosen path across the ground, not just where the airplane’s nose happens to point.
Why Pilots Care
It lets the pilot set and reference a chosen heading at a glance without having to remember numbers.
Intuition Check
Do not read the course arrow as “where the airplane is pointing.” Read it as “the course selected for the airplane to follow.”
Example Sentence 1
Before intercepting the radial, the pilot rotated the course arrow to 270 so the HSI would display guidance for that inbound track.
Example Sentence 2
With the course arrow set to the assigned heading, the pilot cross-checked the heading indicator regularly.