The tide raised in the Earth’s oceans when the Moon is at either first or third quarter phase, and is pulling on the Earth at right angles to the Sun. The amplitude of neap tides (i.e. the difference in water level between high and low tide) is the smallest in the monthly tidal cycle.
Geology and Earth Sciences
Tide of small range occurring every 14 days, near the times of the first and last quarter of the Moon when the Moon, Earth, and Sun are at right angles. The neap tidal range is 10–30% less than the mean tidal range.