What is east or west?

what is east west reversingIs east where the Sun rises and opposite where the sun sets?

Or are east/west located due to the magnetic north? Or physical north? Or found by the North Star or southern cross?

Is east also where physical landmarks are located, like the sea or hills or a town? Especially 1000's of years ago?

What if the sun suddenly rose in the west? Would the east still be east even though the sun use to set in the west?

east west reverseBack in the day was east found by the sun coming from the east and going across the sky, combined with the stars progression across the night sky from east to west?

If the sun rose and progressed the wrong way (the opposite to what it does today) and the stars seemed to have been reversed up and down, then would east still be east?

If there was an earth magnetic field flip and the magnetic north was now in the south then where would be east or west?