Content Types
All SharePoint Lists and Libraries store specific “Categories” of content defined by the SharePoint platform as “Content Types”. For example a Task list generates and stores the Content Type “Tasks”, a Calendar list “Events”, a Library stores file Content Types, i.e. Documents, Images, etc.
SharePoint comes with hundreds of predefined Content Types, organized into several “Parent” categories. The most commonly used categories are List Content Types and File Content Types. Each of these categories can have several sub-types organized hierarchically. (See images below)
The Parent List Content Type is “Item”. Sub-Types under this include Announcement, Comment, Event, Issue, Task, Link and many more.
The Parent File Content Type is “Document” Sub-Types under this include; Basic Page, Form, Picture, Wiki Page and so on.

