is_taxonomy_hierarchical (line 123)
Whether the taxonomy object is hierarchical.

Checks to make sure that the taxonomy is an object first. Then Gets the object, and finally returns the hierarchical value in the object.

A false return value might also mean that the taxonomy does not exist.

return: Whether the taxonomy is hierarchical
since: 2.3.0
uses: is_taxonomy() - Checks whether taxonomy exists
uses: get_taxonomy() - Used to get the taxonomy object
bool is_taxonomy_hierarchical (string $taxonomy)
string $taxonomy: Name of taxonomy object


http://phpdoc.ftwr.co.uk/wordpress/WordPress/Taxonomy/_wp-includes---taxonomy.php.html