(一般作the ebb)
- the movement of the tide out to sea落潮, 退潮：
I knew the tide would be on the ebb
我知道潮水会退去
as modifier the ebb tide.落潮。
短语
at a low ebb
- in a poor state处于低潮, 处于衰落状态：
the country was at a low ebb due to the recent war.
由于最近的战争, 该国处于衰落状态。
ebb and flow
- a recurrent or rhythmical pattern of coming and going or decline and regrowth涨落; 兴衰; 消长。
词源
Old English ebba (noun), ebbian (verb), of West Germanic origin; related to Dutch ebbe (noun), ebben (verb), and ultimately to OF which had the primary sense 'away from'.