Pages is an application in which you can create pages or databases of pages in. Those pages could be named anything you like, and the databases and records could also be named anything you like.
When you are looking at articles, that is just a pages database which has been called articles. Databases contain records that can be given a name. In this case, articles.
So you have articles, which are stored in a database also named articles, which are within the pages application on our software. Of course you can create any number of things with the pages application, rather that articles. In an example here, we have created a database named recipes