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 ...