low tide; low water
Refers to the state of the tide being at its lowest level. Often contrasted with 高潮 (こうちょう, high tide).
See also: 高潮 (こうちょう)
At low tide, the low-water line is clearly visible.
I checked the time of low tide before going fishing.
Compound of 低 (てい, 'low') and 潮 (ちょう, 'tide'). The reading is on'yomi for both characters.