cascade vs cascade down

cascade is a noun but cascade down is not a noun.

Word	Noun	Adjective	Verb	Adverb
cascade	Yes	No	Yes	No
cascade down	No	No	Yes	No

As verbs, cascade and cascade down are synonyms defined as:

cascade (noun)	cascade down (noun)
a sudden downpour (as of tears or sparks etc) likened to a rain shower
a succession of stages or operations or processes or units
a small waterfall or series of small waterfalls

cascade (verb)	cascade down (verb)
arrange (open windows) on a computer desktop so that they overlap each other, with the title bars visible	rush down in big quantities, like a cascade
rush down in big quantities, like a cascade