:the tide when the water is at its highest level高潮;满潮
At high tide the water covers the rocks completely.水达到高潮就会把这些岩石完全淹没。
— sometimes used figuratively有时用作比喻
He became involved in social issues at the high tide of the civil rights movement. [=at the most active and important time of the civil rights movement]他在民权运动达到高潮时开始参与解决社会问题。