WordPress at a glance
action is not described

deleted_(meta_type)meta action-hook . WP 3.4.0

Fires immediately after deleting post or comment metadata of a specific type.

The dynamic portion of the hook, $meta_type, refers to the meta object type (post or comment).

Usage

add_action( 'deleted_(meta_type)meta', 'action_function_name_1993' );
function action_function_name_1993( $meta_ids ){
	// action...
}
$meta_ids(int)
Deleted metadata entry ID.

Where the hook is called

delete_metadata_by_mid()
deleted_(meta_type)meta
wp-includes/meta.php 824
do_action( "deleted_{$meta_type}meta", $meta_id );

Where the hook is used (in WP core)

wp-includes/default-filters.php 95
add_action( 'deleted_post_meta', 'wp_cache_set_posts_last_changed' );
wp-includes/default-filters.php 100
add_action( 'deleted_term_meta', 'wp_cache_set_terms_last_changed' );
wp-includes/default-filters.php 113
add_action( 'deleted_comment_meta', 'wp_cache_set_comments_last_changed' );