Backbone is a lightweight MVC framework primarily used for developing single-page web applications. It relies only on underscore.js and jQuery, making it smaller in size than most frameworks and libraries.
Model—contains the business logic, validations, and data storage for an application. It manages an internal table of data attributes, and triggers "change" events when any of its data is modified.
Collection—an ordered set of models which can bind to events whenever a model in the collection is modified. Like an individual model, a collection fires events whenever a change occurs. Whenever a model is added or removed from a collection a change event is fired.
View—Each view manages the rendering and user interaction within its own DOM element. If you’re strict about not allowing views to reach outside of themselves, it helps keep your interface flexible — allowing views to be rendered in isolation in any place where they might be needed.
Event—a module that can be mixed into any object, giving it the ability to bind and trigger custom named events like user clicks or mouse overs. Events do not have to be declared before they are bound, and may take passed arguments.