A widget is used to pull user focus from one of the top pages down to the module. It may display a hero number or just a few values from the module but can also hold information about deviations happening in the module. It acts as a link or “window” to its module, where the latter holds all information/content.
A module resides in a page and contains all information of a certain subject that might be visually represented as a multiple tables, graphs or even a forms. It could be part of a microsite/SPA or act as its own placeholder.
The Startpage may have an Account-widget that just displays my favourite account that I use every day – but it also tells me if any account is over drafted. It gives me a quick shortcut to go deep in our site structure.