http://www.vizrt.com/types/relation/parent

This link relation identifies a hierarchical relationship to a parent. You can use links of this type to navigate upwards through a tag hierarchy, for example.

The following example shows a link of this type:

<entry>
  ...
    <link 
      rel="http://www.vizrt.com/types/relation/parent" 
      href="http://host-ip-address/webservice/escenic/classification/tag:folksonomy.escenic.com,2002/tag:folksonomy.escenic.com,2002:db:1346" 
      title="politics"/>
  ...
</entry>