Query by Terms

// WP_Query arguments
$args = array(
	'post_type'              => array( 'post' ),
	'post_status'            => array( 'published' ),
	'tax_query'              => array(
		array(
			'taxonomy'         => 'category',
			'terms'            => '$terms',
			'field'            => 'slug',
		),
	),
);

// The Query
$querybyterm = new WP_Query( $args );

// The Loop
if ( $querybyterm->have_posts() ) {
	while ( $querybyterm->have_posts() ) {
		$querybyterm->the_post();
		// do something
	}
} else {
	// no posts found
}

// Restore original Post Data
wp_reset_postdata();