spring tide
Refers to the tide with the greatest difference between high and low water, occurring around new and full moons. Often contrasted with 小潮 (こしお, neap tide).
See also: 小潮
On spring tide days, the ebb and flow of the tide is strong.
During spring tides, the difference between low and high tide is greatest.
Compound of 大 (おお, 'large') and 潮 (しお, 'tide'). The reading おおしお follows standard rendaku rules.