register_taxonomy()

register_taxonomy() — Creates or modifies a taxonomy object. Note: Do not use before the {

Inputs: $taxonomy (string): Taxonomy key. Must not exceed 32 characters and may only contain lowercase alphanumeric characters, dashes, and underscores. See sanitize_key(). $object_type (array|string): Object type or array of object types with which the taxonomy should be associated. $args (array|string): Optional. Array or query string of arguments for registering a taxonomy. Field $labels (string[]): An array of labels for this taxonomy. By default, Tag labels are used for non-hierarchical taxonomies, and Category labels are used for hierarchical taxonomies. See accepted values in get_taxonomy_labels(). Default empty array. Field $description (string): A short descriptive summary of what the taxonomy is for. Default empty. Field $public (bool): Whether a taxonomy is intended for use publicly either via the admin interface or by front-end users. The default settings of $publicly_queryable, $show_ui, and $show_in_nav_menus are inherited from $public. Field $publicly_queryable (bool): Whether the taxonomy is publicly queryable.

Returns WP_Taxonomy|WP_Error: The registered taxonomy object on success, WP_Error object on failure.