The term "mobile application" is used quite loosely these days. Typically, when someone says "mobile application" they are referring to one of two types of applications:
Mobile-optimized web application
Natively installed mobile application
The first type is simply a web application that runs in the browser, but is optimized for the smaller screens typical in mobile devices like phones and tablets. This type of application is no different from any other web application. It executes in the browser, and so the same rules and considerations apply to it regardless of whether it is a mobile browser or a desktop browser.
The second, however, is of more importance to us. This type of application represents natively installed applications on mobile devices, an entirely new platform in recent years. From here on, when we mention "mobile applications", we are referring to this second category of applications, natively installed mobile applications, and not mobile-optimized...