What is the difference between softwares and apps?

It is a pretty regular question nowadays for beginners in software industries. People often get confuse between apps and softwares. A common myth is that app developers are not software engineers or developing apps is not the thing that called software engineering. But the truth is all apps developers are software engineers but not all software engineers are app developer. You can call an app a branch of software or a group of software. Little bit tricky? Yes it is because software is the mother of all of the soft components of any computable devices. For example suppose your personal computer runs with windows operating system in which you can run many softwares microsoft excel, MS-word, adobe photoshop or any other microsoft apps that provide by the company or app store of windows. So, if you call these softwares, then what is operating system? Is it a hardware or software or can it be called an app? It is not a hardware compound for sure as it cannot be touched and it doesn't have a visual existence. Actually any operating system (Macintosh, Windows, Android, Linux, Ubunto) all are special types of softwares which directly work with computing memory and processing unit or hardware. The rest of the softwares or apps communicate with hardware with the help of operating system. So we can call it a special type of software which directly communicate with hardware to support other funtional apps to run side by side in computer devices. Commonly they are the same thing in different names. The software that runs on a Android device is called android app. There is no deference between softwares and apps. Like Microsoft has office, excel apps on their own Windows operating system. Android is also a operating system which is made from linux based kernel but it runs on small device like smart phone. Also you can run android app on windows too with bluestack or any other android emulator that temporary creates an operating system in small memory of your pc. And you can also find microsoft apps like word, excel etc in google play store which is developed for running on android opetating system. There is a similar process of developing android apps and pc softwares. Android's native language is Java, and you can make any software even you can make a complete website with Java which can run on server. Software Engineers works with softwares or apps that doesn't mean that they won't know about hardware or how their app is operting with hardware through operating system. It is a complete engineering.