amphidromic point The centre of a tidal system; it is a no-tide or nodal point around which the crest of a standing wave or a high-water level rotates once in each tidal cycle. The tidal range increases progressively with increasing distance from the central point. The high water rotates anticlockwise around the central point in the northern hemisphere and clockwise in the southern hemisphere. The word ‘amphidromic’ is derived from an Attic festival, the Amphidromia, at which friends carried a young child around the hearth and then named it.

amphidromic point The centre of an amphidromic or tidal system; a no-tide or nodal point around which the crest of a standing wave or a high-water level rotates once in each tidal cycle. The tidal range increases progressively with increasing distance from the central point. The high water rotates anticlockwise around the central point in the northern hemisphere and clockwise in the southern hemisphere.