half tide; moderate tide
Refers to a tide of moderate range, occurring midway between spring and neap tides. Used in marine and fishing contexts.
中潮の日は潮の流れが穏やかで、釣りに適している。
On days with a moderate tide, the current is gentle and suitable for fishing.
Compound of 中 (naka, 'middle') and 潮 (shio, 'tide'), literally 'middle tide'.