Definition
The specified inbound track that an aircraft flies toward the holding fix when established in a holding pattern. It defines the direction of the inbound leg and is the reference from which the rest of the pattern (outbound leg, turns, and protected airspace) is built.
Plain English
The line you fly inbound to the holding point. Everything else in the holding pattern is shaped around this line.
Context Anchor
Seen in instrument holding instructions and holding-pattern diagrams, especially when identifying the inbound leg to the holding fix.
Derivation
Course comes from an older word meaning a run, path, or direction of travel. In aviation, that idea became the planned direction an aircraft follows across the ground.
Why Pilots Care
Keeps the aircraft inside protected airspace and aligned for the next approach segment.
Intuition Check
Do not read holding course as the whole route you fly while waiting. In this context, it means the specific inbound direction back to the holding fix.
Example Sentence 1
ATC issued the clearance to hold east of the VOR on the 090 radial, making the holding course 270 inbound to the fix.
Example Sentence 2
Once established, ATC cleared the aircraft to continue on the holding course until further notice.