parent

Hypertext links in HTML (draft)

      PARENT
         The PARENT relationship identifies the superior or container
         node.

         When REL=PARENT, the target document is the hierarchical
         parent, or container, of the current document.

         When REV=PARENT, the current document is the hierarchical
         parent, or container, of the target.

         If the hypertext link is specified with REL in a LINK element,
         an HTML user agent may present an icon in a tool bar.

[引用： 4.4d. Hierarchy Links -- Hypertext links in HTML (draft) より]