It's purely a problem of terminology. An app is just the name for a component which has a somewhat predefined structure - model, urls, tests, etc. The django framework then loads these components and makes the various part of the structure available within the project. An app, sorry, component can be simply a model or a complete sub-system with templates, views, javascript files, etc. The general idea is to factor out the reusable stuff into components which can then be easily configured for any given project.