a unit of volume of water in irrigation: the amount covering one acre to a depth of one foot, equal to 43,560 cubic feet.
Origin of acre-foot
An Americanism dating back to 1900–05
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
noun plural -feet
the volume of water that would cover an area of 1 acre to a depth of 1 foot: equivalent to 43 560 cubic feet or 1233.5 cubic metres
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