alluvion has definitions from the field of geology
1
[ noun ] (geology) clay or slit or gravel carried by rushing streams and deposited where the stream slows down

Related terms

sediment placer alluvial_soil

2
[ noun ] (geology) the rising of a body of water and its overflowing onto normally dry land

Examples

"plains fertilized by annual inundations"

3
[ noun ] (geology) gradual formation of new land, by recession of the sea or deposit of sediment

Related terms

geological_process

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