A website is intended for the user to read it and submit forms. A webapp, like a mobile app are intended for the user to make selections on a pathway to a specific outcome. Both website and web app are presented to the end user on the users browser. A mobile app is not located on a browser, it is software on the device like word or excel on your desktop for example. (Mobile) Apps are typically governed by the conditions of the stores as they have better access to a users device and potentially sensitive data and actions.