We have finally reached the point where we talk about the most complex, robust, and powerful system for modeling data and content in Drupal 8--the Entity API.
Entities have been around since Drupal 7, which shipped with a few types such as node, taxonomy terms, users, comments, files, and so on. However, Drupal core only provided a basic API for defining entities and loading them consistently. The Entity API contributed module bridged a large gap and provided a lot of functionality to make entities much more powerful. In Drupal 8, however, these principles (and more) are found in core as part of a robust data modeling system.
The Entity API integrates seamlessly with the multilingual system to bring fully translatable content and configuration entities. This means that most data you store can be translated easily into multiple languages. In Drupal 7, this was always a...