alluvion vs alluvium

alluvion and alluvium both are nouns.

Word	Noun	Adjective	Verb	Adverb
alluvion	Yes	No	No	No
alluvium	Yes	No	No	No

As nouns, alluvion and alluvium are synonyms defined as:

alluvion and alluvium: clay or silt or gravel carried by rushing streams and deposited where the stream slows down

Other synonyms of alluvion include alluvial deposit, alluvial sediment.

alluvion (noun)	alluvium (noun)
clay or silt or gravel carried by rushing streams and deposited where the stream slows down	clay or silt or gravel carried by rushing streams and deposited where the stream slows down
the rising of a body of water and its overflowing onto normally dry land
gradual formation of new land, by recession of the sea or deposit of sediment