Dan Luke wrote:
"Dennis Johnson" wrote:

How would that be different if I were given the same instructions, except
hold on the 180° course (instead of the 180° radial)?

You won't be given that instruction, at least not by a controller who knows
what he's doing.

The only context in which "course" might be used, that I can think of,
is where you might be cleared to hold on a "final approach course".

DB