Types of information in Drupal.
Drupal has several distinct types of information, each with its own methods for storage and retrieval:
Content: Information meant to be displayed on your site: articles, basic pages, images, files, custom blocks, etc. Content is stored and accessed using Entities.
Session: Information about individual users' interactions with the site, such as whether they are logged in. This is really "state" information, but it is not stored the same way so it's a separate ty