Here's my take, based on going back many years.
A menu bar is the old across the top File Tools About and anything in between that pertains to the application. You click a menu item and maybe sub menus appear, maybe not. It's housed in a command bar. A tool bar is the menu bar, but with icons, not text menus. It is also contained in a command bar. Clicking an icon never produced a menu or sub menu if I recall correctly, just launched a process. A right click menu is a context menu, not a menu bar. AFAIK, they do not have sub menus.
As late as 2007 version, I was able to use old code from 2003 to maintain and even modify menu bars. My choice seemed to be hide the ribbon (which could also hide other needed functionality) and show the menu, or have the menu appear in the ribbon because I wasn't interested in delving into the realm of creating my own ribbon. Seems I was determined to resist being assimilated. I've since retired, so I have little idea of how the apps look now, even though I know they're still being used.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.