noun
- a mark showing the highest level reached by a body of water.
- the highest point of anything; acme: Her speech was the high-water mark of the conference.
noun
-
- the level reached by sea water at high tide or by other stretches of water in flood
- the mark indicating this level
- the highest point
The peak of something, especially an achievement. For example, This composition is the high-water mark of his entire output. This expression alludes to the highest mark left on shore by the tide. [Mid-1800s]