high-water mark
noun /ˌhaɪ ˈwɔːtə mɑːk/
/ˌhaɪ ˈwɔːtər mɑːrk/
- a line or mark showing the highest point that the sea or floodwater has reached
- We pulled the boat up the beach above the high-water mark.
- (figurative) the high-water mark of Parisian fashion (= the most successful time)