flood plain

or flood·plain


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


Nearby words

  1. flood,
  2. flood basalt,
  3. flood control,
  4. flood insurance,
  5. flood lamp,
  6. flood tide,
  7. flood wall,
  8. flooded gum,
  9. flooders,
  10. floodgate

Origin of flood plain

First recorded in 1870–75

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for floodplain

flood plain


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

Word Origin and History for floodplain



also flood plain, 1873, from flood (n.) + plain (n.).

Online Etymology Dictionary, © 2010 Douglas Harper

Science definitions for floodplain


[ flŭdplān′ ]

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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.