App is actually correct for all but the OS.

The word app has been around forever, first appearing in the 1970s (according to some dictionaries I just googled). Pendulum swung towards “programs” and we have since swung back to the correct term.

I think both are fine. Regular people don't need more than "app", but professionals still know and use other words too.

Double plus good!

The braces are nice touch.

In my workplace they use robot for everything

thing and stuff