alluvium

[uh-loo-vee-uhm]

noun

plural

alluviums, alluvia 

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.

alluvium

/ əˈluːvɪəm /

noun

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

alluvium

plural

alluviums 

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.

Word History and Origins

Origin of alluvium¹

1655–65; < Latin, noun use of neuter of alluvius washed against, equivalent to alluv- ( alluvion ) + -ius, -ium adj. suffix; -ium

Word History and Origins

Origin of alluvium¹

C17: from Latin; see _alluvion

Example Sentences

Deposits of alluvium and volcanic ash have made desirable soil that is among the top 2% in the world.

From Seattle Times

Paved surfaces end miles from the rock outcrop, so we drive on overgrown rutted two-tracks that cross the loose sandy dune fields that show up on our geologic maps as “QAL”—Quaternary alluvium.

From Scientific American

“Great buildings, like great mountains, are the work of centuries,” Hugo says, whereby “each wave of time lays down its alluvium”.

From The Guardian

The island’s geology — a heart of granite in the west, compacted alluvium in the east — is such that most of it could be hollowed out.

From New York Times

“In a way, the flood is a blessing as fresh silt and alluvium deposits increase the productivity of the forest undergrowth,” Das tells the Hindu.

From National Geographic

Related Words

• clay 
• coast 
• dirt 
• dust 
• gravel 
• land 
• mud 
• sand 
• shore 
• surface 
• terrain 
• turf