flood plain

American  

Or floodplain

noun

1. a nearly flat plain along the course of a stream or river that is naturally subject to flooding.

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flood plain British  

noun

1. the flat area bordering a river, composed of sediment deposited during flooding

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Etymology

Origin of flood plain

First recorded in 1870–75

Example Sentences

See Examples For:

flood plain

The land sits on low ground and would need fill for any redesign, to get it above the Potomac river flood plain.

From The Wall Street Journal ● Dec. 13, 2025

It might be that in an era of what researchers are calling “mega rain” events, a flood plain should now be off-limits.

From Salon ● Jul. 10, 2025

Other factors officials should consider is whether critical infrastructure, such as airports, would fall within the quake-expanded flood plain, scientists say.

From Los Angeles Times ● Apr. 30, 2025

Water voles now roam the network of channels, streams, and ponds the beavers use to navigate the flood plain.

From BBC ● Feb. 28, 2025

Near the far edge of the flood plain I find Alice’s footsteps in a stretch of muddy sand.

From "On the Far Side of the Mountain" by Jean Craighead George