neap tide
noun/ˈniːpˌtaɪd/ · /ˈnɪpˌtaɪd/
Etymology From neap + tide. Compare Danish niptid (“neap tide”), German Nipptide (“neap tide”), Old English nēpflōd (“neap tide”).
1
The tide which occurs just after the first and third quarters of the moon, when there is least difference between high tide and low tide.
- Spring tides occur when the Sun and Moon line up, since the gravities of the two bodies add together to create larger tidal forces. Neap tides occur when the Sun and Moon are at right angles to one another as seen from Earth. In this case, the gravitational forces counteract each other, creating weaker tidal forces.1992 July 23, Neil F. Comins, “A New Slant on Earth”, in Astronomy, volume 20, number 7, page 44:
- Rear Adm. Harry Hill, put in command of the amphibious force, consults with local mariners and reaches a cautious consensus that neap high tide in the lagoon on November 20 will surely be close to five feet deep.1993 November 23, Michael Kernan, (Tarawa), “...heavy fire...unable to land...issue in doubt.”, in Smithsonian, volume 24, number 8, page 118:
1 more example
- ... and neap tides (tides that occur during the first and third quarters of the moon and that have the least difference between high and low tides), ...1995, Richard M. Schlenker, Sarah J. Yoshida, “Developing Science Activities”, in Science Activities, volume 32, number 2, page 34: