In iis you can have a Site with many sub-Applications. Per iis.net:
In IIS 7 and above, each site must have an application which is named the root application, or default application. However, a site can have more than one application. For example, you might have an online commerce Web site that has several applications, such as a shopping cart application that lets users gather items during shopping and a login application that allows users to recall saved payment information when they make a purchase.