Definition
On a Horizontal Situation Indicator (HSI), the course select pointer is the arrow-shaped indicator that the pilot rotates around the compass card to set the desired course. The head of the arrow points to the selected course heading on the compass card, and the tail points to the reciprocal. The course deviation bar moves laterally relative to this pointer to show the aircraft's position left or right of the selected course.
Plain English
It is the arrow on the HSI that the pilot turns to point at the course they want to fly. Once set, the rest of the instrument shows whether the aircraft is on that course or off to one side.
Context Anchor
Seen on the face of an HSI during instrument navigation, especially when setting a course to follow a navigation signal or a published approach course.
Derivation
"Course select" describes its function -- the pilot uses it to select a course. "Pointer" comes from Middle English, meaning something that points or indicates. Together: the arrow you set to point at your chosen course.
Why Pilots Care
Setting the course select pointer correctly is essential for navigation. If it is set to the wrong course, the deviation bar will give misleading guidance and the pilot may track an incorrect path -- a serious issue during approaches or airway navigation.
Intuition Check
Do not read course here as a class or as simply the direction the nose of the aircraft is pointing. Here, course means the selected path the pilot wants the aircraft to follow.
Example Sentence 1
Before intercepting the airway, the pilot rotated the course select pointer to 270 degrees on the HSI.
Example Sentence 2
With the course select pointer set to the final approach course, the pilot monitored the deviation bar for left or right corrections.