Extension – Collection of directories and files under one main directory that can be added to shopping cart to offer additional feature or function. Extension can be enabled and configured in the admin of shopping cart application
Extension Configuration – Collection of settings that can control the extension functionality of behavior. Configuration can be default (provided with the original installation of the extension) and custom, after installation once admin user change the settings.
Hook – This is the tool used in extension subsystem to connect extension to particular section in application.
Core Hook – This is the hook to the core function of application that allows extending functionality, effect data structures and values.
Template Hook - This is the hook to extend display of the particular page on the front end or admin. This is usually implemented within template file.
Dataset - Ability to save, access and manage data specific for extension. See more details later on.