Register a Taxonomy

posttype.php

<?php // Don't include this more than once in your file

/**
 * Create taxonomy for testimonials CPT.
 *
 * Registers a hierarchical (like categories) taxonomy for the testimonials custom post type
 *
 * @see register_taxonomy
 */
add_action( 'init', 'fcwp_testimonials_tax' );
function fcwp_testimonials_tax() {
	$labels = array(
		'name'              => _x( 'Testimonial Categories', 'taxonomy general name' ),
		'singular_name'     => _x( 'Testimonial Category', 'taxonomy singular name' ),
		'search_items'      => __( 'Search Testimonial Categories' ),
		'all_items'         => __( 'All Testimonial Categories' ),
		'parent_item'       => __( 'Parent Testimonial Category' ),
		'parent_item_colon' => __( 'Parent Testimonial Category:' ),
		'edit_item'         => __( 'Edit Testimonial Category' ),
		'update_item'       => __( 'Update Testimonial Category' ),
		'add_new_item'      => __( 'Add New Testimonial Category' ),
		'new_item_name'     => __( 'New Testimonial Category' ),
		'menu_name'         => __( 'Testimonial Categories' ),
	);
	$args = array(
		'hierarchical'      => true,
		'labels'            => $labels,
		'show_ui'           => true,
		'show_admin_column' => true,
		'query_var'         => true,
		'rewrite'           => array( 'slug' => 'testimonial-categories' ),
	);
	register_taxonomy( 'testimonials-tax', 'testimonial', $args );
}