You just made my brain click. I’ve always wondered why clockwise rotation around a vertical axis was commonly agreed. I have never seen a mechanical- or electrical clock installed flat on the ground. So why would we assume that the clock isn’t in the ceiling facing down, which would reverse the direction?
But now that you mention it in the context of a sundial, it seems so obvious that the clock is just an extension of that, making the sun and clock a common reference.
But that bids the question if they have another term for it in the southern hemisphere.