public function mb_relationships_init() {

			MB_Relationships_API::register(
				[
					'id'         => 'words_to_words_synonyms',
					'from'       => [
						'object_type'  => 'post',
						'post_type'    => 'word',
						'admin_column' => [
							'title' => 'Synonyms',
							'link'  => 'edit',
						],
						'meta_box'     => [
							'title' => 'Synonyms / Connected words (same part of speech)',
						],
					],
					'to'         => 'word',
					'reciprocal' => true
				] );

			MB_Relationships_API::register(
				[
					'id'         => 'words_to_words_related',
					'from'       => [
						'object_type'  => 'post',
						'post_type'    => 'word',
						'admin_column' => [
							'title' => 'Related',
							'link'  => 'edit',
						],
						'meta_box'     => [
							'title' => 'Related / Connected words (different parts of speech)',
						],
					],
					'to'         => 'word',
					'reciprocal' => true
				] );
		}