cascading menu vs submenu

cascading menu and submenu both are nouns.

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

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

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

Other synonyms of cascading menu include hierarchical menu.

cascading menu (noun)	submenu (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