An orphan node is defined as a node that exists in a version but is not assigned to a hierarchy within the version. Orphans may exist pending a cleanup to completely remove them, or they may be awaiting reassignment to hierarchies in the version.
Although they are not associated with any hierarchy, orphan nodes can have global relationships to other nodes in the version. It is possible for an orphan node to have descendants that are not orphans. To avoid this, review the list of orphan nodes regularly.
For more information, see: