Any Addon that utilizes infusion.php to modify the Core database is called an Infusion.
Themes control the layout and the graphical design of your site´s front-end.
Admin Themes controls the style and the graphical design of your Administration area.
You can find our Themes in the Themes Directory
Any Addon that are designed by the Widgets API will be defined as a Widget.
Any Addon that creates either a center or side Panel is defined as a Panel.
All other Addons including BBCodes, User Fields, Graphics and Core modifications are simply defined as Other.