Amphidromic point, or amphidrome, is a point in the
sea that has no tidal amplitude, that is, a point where there is never any change in the height of the water due to tides.
The tides oscillate around this peculiar place: the cotidal lines radiate from it, connecting points which have simultaneous cycles of tides, while the corange lines encircle it, connecting points that have the same delta between the water level at high and low tide.
High water rotates around the amphidromic point counterclockwise in the northern hemisphere and clockwise in the southern hemisphere.
These different movements exist as a result of the Earth's rotation and the so-called Coriolis force.