also: さかしお
noun
adverse current; weather tide
A nautical term for a current or tide flowing against the direction of a vessel, making navigation difficult. The reading ぎゃくちょう is standard; さかしお is rare.
船は逆潮に逆らって進んだ。
The ship advanced against the adverse current.
逆潮のため、港への到着が遅れた。
Due to the adverse tide, arrival at the port was delayed.
Compound of 逆 (reverse) and 潮 (tide). The reading ぎゃくちょう uses the on'yomi of both characters, while さかしお uses the kun'yomi of 逆 and the on'yomi of 潮.