I have started learning Django, I'm not sure what the **include()** function means.

Here is ***mysite/urls.py***. - **project**

```
from django.conf.urls import include, url
from django.contrib import admin

urlpatterns = [
    url(r'^polls/', include('polls.urls')),
    url(r'^admin/', admin.site.urls),
]

```

Here is ***polls/urls.py***. - **app in project**

```
from django.conf.urls import url
from . import views

urlpatterns = [
    url(r'^$', views.index, name='index'),
]

```

From django document, **include()** function was described as follows.

> 
> Whenever Django encounters include(), it chops off whatever part of the URL ***matched up to that point*** and sends the ***remaining string*** to the included URLconf for further processing.
> 
> 
> 

I'm not sure what is **that point**, what is **remaining string**.

In case of the example above, what is **remining string**, what is **url** strings which was chopped off?