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[uh-loo-vee-uh m]
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noun, plural al·lu·vi·ums, al·lu·vi·a [uh-loo-vee-uh] /əˈlu vi ə/.
  1. a deposit of sand, mud, etc., formed by flowing water.
  2. the sedimentary matter deposited thus within recent times, especially in the valleys of large rivers.
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Origin of alluvium

1655–65; < Latin, noun use of neuter of alluvius washed against, equivalent to alluv- (see alluvion) + -ius, -ium adj. suffix; see -ium
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words


Examples from the Web for alluvium

Historical Examples

  • If so, the thickness of the alluvium is at least 1800 ft., and may be much more.

    Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 4


  • Here I had an opportunity of seeing the material of which the alluvium is composed.

    Notes on the Fenland

    T. McKenny Huges

  • Strata intersected by a trap dike, and covered with alluvium.

  • It would be interesting to know the thickness of the alluvium.

  • This growth rarely takes place from the waste of the bed rocks on which the alluvium lies.

    Outlines of the Earth's History

    Nathaniel Southgate Shaler

British Dictionary definitions for alluvium


noun plural -viums or -via (-vɪə)
  1. a fine-grained fertile soil consisting of mud, silt, and sand deposited by flowing water on flood plains, in river beds, and in estuaries
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Word Origin

C17: from Latin; see alluvion
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 alluvium


"matter deposited by flowing water," 1660s, from Medieval Latin alluvium, neuter of alluvius "washed against," from Latin alluere "wash against," from ad- "to, against" (see ad-) + -luere, comb. form of lavere "to wash" (see lave).

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Online Etymology Dictionary, © 2010 Douglas Harper

alluvium in Science


Plural alluviums alluvia
  1. Sand, silt, clay, gravel, or other matter deposited by flowing water, as in a riverbed, floodplain, delta, or alluvial fan. Alluvium is generally considered a young deposit in terms of geologic time.
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Related formsalluvial adjective
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.