alluviuma deposit of sand, mud, silt, or gravel formed by flowingNot to be confused with:alluvion ? overflow; floodeluvium ? a deposit of soil, dust, or rock debris formed by the decomposition of rockilluvium ? the material accumulated through soil that has been leached out of another layer of soilAbused, Confused, & Misused Words by Mary Embree Copyright © 2007, 2013 by Mary Embreeal·lu·vi·um (?-lo?o?v?-?m)n. pl. al·lu·vi·ums or al·lu·vi·a (-v?-?) Sediment deposited by flowing water, as in a riverbed, flood plain, or delta. Also called alluvion.[Medieval Latin, flood, from neuter of Latin alluvius, alluvial, from alluere, to wash against; see alluvion.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.alluvium (??lu?v??m) n, pl -viums or -via (-v??) (Geological Science) a fine-grained fertile soil consisting of mud, silt, and sand deposited by flowing water on flood plains, in river beds, and in estuaries[C17: from Latin; see alluvion]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014al?lu?vi?um (??lu vi ?m) n., pl. -vi?ums, -vi?a (-vi ?) 1. a deposit of sand, mud, etc., formed by flowing water. 2. the sedimentary matter deposited thus within recent times, esp. in the valleys of large rivers. [1655?65;