flood plain

or floodplain

See synonyms for flood plain on Thesaurus.com
  1. a nearly flat plain along the course of a stream or river that is naturally subject to flooding.

Origin of flood plain

First recorded in 1870–75

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use flood plain in a sentence

British Dictionary definitions for flood plain

flood plain

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

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for floodplain


[ flŭdplān′ ]

  1. Flat land bordering a river and made up of alluvium (sand, silt, and clay) deposited during floods. When a river overflows, the floodplain is covered with water.

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