/ Dictionary / Index A alluvium: Meaning and Definition of Find definitions for: al•lu•vi•um Pronunciation: (u-l'vē-um), [key] — pl. -vi•ums, -vi•a a deposit of sand, mud, etc., formed by flowing water. the sedimentary matter deposited thus within recent times, esp. in the valleys of large rivers. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: alluvium (Thesaurus) alluvion all-weather Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language