high-water mark

American  

[hahy-waw-ter, -wot-er] / ˈhaɪˈwɔ tər, -ˈwɒt ər /

noun

1. a mark showing the highest level reached by a body of water.

2. the highest point of anything; acme.

   Her speech was the high-water mark of the conference.

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high-water mark British  

noun

1. 1. the level reached by sea water at high tide or by other stretches of water in flood

   2. the mark indicating this level

2. the highest point

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high-water mark Idioms  

1. 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]

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Etymology

Origin of high-water mark

First recorded in 1545–55

Example Sentences

Still, the CBA deal is a high-water mark for a league with a tumultuous history.

From The Wall Street Journal • Mar. 20, 2026

The increase in consumer prices in the 12 months ended in November could inch up to 3.1% from 3.0%, potentially the high-water mark due to tariffs.

From MarketWatch • Dec. 17, 2025

Now they’re down only 25% from that 2022 high-water mark.

From Barron's • Oct. 28, 2025

They've come to see that moment of celebration after the inquests as their high-water mark.

From BBC • Sep. 15, 2025

When the counterfeit Beast was perfected, the knights took it away and hid it in a cave at the foot of the cliffs, above high-water mark.

From "The Once and Future King" by T. H. White

Related Words

• apex
• apogee
• upper limit