neap

Neap refers to a type of tide, specifically a neap tide, a tide with a smaller tidal range that occurs roughly twice each lunar month. This happens during the first and third quarters of the Moon when the Sun and Moon are at right angles to the Earth. At these times, their gravitational forces partly cancel each other, causing high tides to be lower and low tides to be higher than average. The resulting difference between successive high and low water levels is at its minimum for the lunar month.

The magnitude of a neap tide depends on local factors such as coastline shape, water depth, and seabed topography, so observed effects vary by location. Neap tides are part of the regular lunar cycle of tides and contrast with spring tides, which occur at full Moon and new Moon when solar and lunar gravities reinforce each other and produce larger tidal ranges.

In practical terms, neap tides can influence coastal activities that rely on tidal highs and lows, including navigation in shallow waters, fishing patterns, and some tidal energy operations. They also affect the distribution and exposure of intertidal habitats, albeit typically to a subtler degree than spring tides.

Etymology and usage: The term neap is used in nautical and astronomical contexts and has been part of English tide-related vocabulary for centuries. Its origin is uncertain, but it is specifically tied to tides rather than general usage of the word neap.