Denotes the products with type as configurable.
Configurable product is one of the default product types of Magento.
These products can only be created on the basis of product attribute(s) which are drop-downs and are selected to be used for configurable products.
Each option (or combination of options) will generate a simple product which will be called as associated product.
The configurable products will show the option(s) as drop-down(s) on frontend.
Any product attribute used to create the configurable product can't be deleted unless the configurable product is deleted.