The definitions are infinite and can vary from the most generic possible, where the terms can probably be considered synonymous, the most methodical definitions resorting to the origins of the spelling of words and the context of emergence, where probably some of the terms may discriminate.
In a quick analysis on my part, without resorting to great research and focusing on the context of use, I believe that what is most distinguished from the others is the term "App", which naturally refers us to mobile apps. Just a googlada will see that the biggest references are in this mobile context.
Follow the first definition I found:
App is a nickname given to the term "app" (which comes from the English application). You will also hear other ways to call the App such as: mobile app, mobile app, mobile app.
But after all, what is an App? - App Factory Blog https://blog.fabricadeaplicativos.com.br manufactures but-after-what-and-an-app
You defined both the source code and the compiled code, correct? And this definition of App Was it used before the iPhone? I wasn’t a smartphone user at the time so I can’t say, I just know that I don’t remember that term used for non-smart phones.
– Piovezan