Fixed #25748 -- Added clarification on projects vs. applications.

Projects and applications

=========================

Django has historically used the term **project** to describe an installation

of Django. A project is defined primarily by a settings module.

The term **project** describes a Django web application. The project Python

package is defined primarily by a settings module, but it usually contains

other things. For example, when you run  ``django-admin startproject mysite``

you'll get a ``mysite`` project directory that contains a ``mysite`` Python

package with ``settings.py``, ``urls.py``, and ``wsgi.py``. The project package

is often extended to include things like fixtures, CSS, and templates which

aren't tied to a particular application.

The term **application** describes a Python package that provides some set of

features. Applications may be reused in various projects.

.. note::

    This terminology is somewhat confusing these days as it became common to

    use the phrase "web app" to describe what equates to a Django project.

features. Applications :doc:`may be reused </intro/reusable-apps/>` in various

projects. A project's root directory (the one that contains ``manage.py``) is

usually the container for all of a project's applications which aren't

installed separately.

Applications include some combination of models, views, templates, template

tags, static files, URLs, middleware, etc. They're generally wired into

introspection. That's why the application registry maintains metadata in an

:class:`~django.apps.AppConfig` instance for each installed application.

There's no restriction that a project package can't also be considered an

application and have models, etc. (which would require adding it to

:setting:`INSTALLED_APPS`).

.. _configuring-applications-ref:

Configuring applications