A web app is simply an app that you can use without even having to install it. This is mainly because it is necessarily a link to a website that is designed to look like a normal app. All the resources are stored in the cloud and the processing happens there as well. This is why web apps are much lighter (occupy a fraction of the memory) and are much faster than conventional apps.
It must also be noted that since web apps are simply a link to a website and most of the UI/UX components exist in the cloud, a good network connection is quintessential for their working.
The primary reason that this kind of application is opted is when the speed of operation and low memory consumption is a high priority and simplicity, ease of access is also an integral part of the design.
Advantages:
Following are the primary advantages of a web app:
1.  Large target audience as same web apps can work seamlessly between desktops and mobile platforms
2.  Easy multi-platform development
3.  Easy to update and maintain across all platforms
4.  No direct certification needed
Disadvantages:
Following are the disadvantages:
1.  Reliance on Internet, major functionality loss in case of connectivity hiccups.
2.  Older operating system platforms might not support them
Comparison with Conventional Apps:
That’s it for today folks! Hope you learned something useful!
Topic covered yesterday: What is software development lifecycle?
Topic for tomorrow: What is a domain name?
Signing off!
Onwards and Upwards!