flood plain
or flood·plain
noun
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
Words nearby flood plain
flood,
flood basalt,
flood control,
flood insurance,
flood lamp,
flood plain,
flood tide,
flood wall,
flooded gum,
flooders,
floodgate
British Dictionary definitions for floodplain
flood plain
noun
the flat area bordering a river, composed of sediment deposited during flooding
Scientific definitions for floodplain
floodplain
[ flŭd′plān′ ]
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.