submenu vs cascading menu

submenu and cascading menu both are nouns.

Word	Noun	Adjective	Verb	Adverb
submenu	Yes	No	No	No
cascading menu	Yes	No	No	No

As nouns, submenu and cascading menu are synonyms defined as:

submenu and cascading menu: a secondary menu that appears while you are holding the cursor over an item on the primary menu

Other synonyms of submenu include hierarchical menu.

submenu (noun)	cascading menu (noun)
a secondary menu that appears while you are holding the cursor over an item on the primary menu	a secondary menu that appears while you are holding the cursor over an item on the primary menu