If your Magento installation has a hierarchy of websites, stores, or views, you can set the context, or “scope” of a configuration setting to apply to a specific part of the installation. The context of many database entities can also be assigned a specific scope to determine how it is used in the store hierarchy. To learn more, see: Product Scope and Price Scope.
Some configuration settings such as postal code, have a [global] scope because the same value is used throughout the system. The [website] scope applies to any stores below that level in the hierarchy, including all stores and their views. Any item with the scope of [store view] can be set differently for each view, and is typically used to support multiple languages.
Unless the store is running in Single Store Mode, the scope of each configuration setting appears in small text below the field label. If your installation includes multiple websites, stores or views, you should always choose the Store View where the settings apply before making any changes.
System-wide settings and resources that are available throughout the Magento installation.
Settings and resources that are limited to the current website. Each website has a default store.
Settings and resources that are limited to the current store. Each store has a default root categoryA set of products that share particular characteristics or attributes. (main menu) and default store view.