high-water line

noun

variants or high-water mark

1

a

: the line of the shore of the sea or of a lake or river to which the waters usually reach at high water:

(1)

: the line that marks the limit of the rise of the medium tides of the sea between the spring and neap tides

(2)

: the line that marks the limit of the soil so affected by the water of a lake or river as to have a nature and vegetation distinct from that of the banks

b

: a mark showing the highest level reached by a body of water

2

usually high-water mark : the highest point : acme

the high-water mark of a girl's social career

—Hamilton Basso

Word History

First Known Use

1691, in the meaning defined at sense 1a

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