Distant parent

The distantparent module lets you make one taxonomy term the child of another term in a different vocabulary. Distant parent relationships are added and edited through the administration interface.

Note: this module has been deprecated, and is no longer being maintained. It is highly recommended that you use the category module instead, as this module has built-in distant parent functionality, which is far superior to what is offered in this module.

Note that this module is only concerned with the management of distant parents, not the actual use of them by Drupal's taxonomy system. See this article on cross-vocabulary hierarchies for a tutorial (with code samples, screenshots, and patch files) explaining how to get breadcrumbs that are distant-parent aware.