alluvial sediment vs sediment

alluvial sediment and sediment both are nouns.

Word	Noun	Adjective	Verb	Adverb
alluvial sediment	Yes	No	No	No
sediment	Yes	No	Yes	No

As nouns, sediment is a hypernym of alluvial sediment; that is, sediment is a word with a broader meaning than alluvial sediment:

alluvial sediment: clay or silt or gravel carried by rushing streams and deposited where the stream slows down
sediment: matter that has been deposited by some natural process

Other hypernyms of alluvial sediment include deposit.

alluvial sediment (noun)	sediment (noun)
clay or silt or gravel carried by rushing streams and deposited where the stream slows down	matter that has been deposited by some natural process

alluvial sediment (verb)	sediment (verb)
	settle as sediment
	deposit as a sediment