Media Settings : The Categories Module
  
The Categories Module
Use the Categories module to create a content classification system for your user’s content.
 
The Categories module displays:
Column
Description
Category Name
The name of the category. Click to edit a category.
Items
The number of items (media) that have been assigned to a category.
Actions
The actions you may perform on a Category.
●Delete — When a category is deleted, the content associated to it is not deleted; only the association itself. Deleting a category will also delete all subcategories associated with the category.
 
Additional functionality:
Function
Description
Create Category
Creates a new category.
Add Child
Adds a subcategory to the category.
 
*See Also:
Allow Categories on All Media
Add or Delete a Category or Subcategory From a Video
Bulk Editing Video Categories