An application is an instance of TApplication or its derived class. Each PRADO application consists of a single application instance, one or several services, and some modules. For applications providing the page service (true for nearly all applications), they also contain one or several pages.
The application instance is the only object that is accessible globally via Prado::getApplication() function call. It manages modules that provide different functionalities and are loaded when needed. It holds services that are available to end-users. An application instance may be configured via application configurations.
An application instance is usually created in an entry script in a PRADO application, as shown in the following,
require_once('/path/to/prado.php');
$application = new TApplication;
$application->run();
where the method run() starts the application to handle user requests.
TBD