WordPress at a glance
action is not described

woocommerce_before_single_product action-hook . WC 1.0

Hook: woocommerce_before_single_product.

Usage

add_action( 'woocommerce_before_single_product', 'action_function_name_7497' );
function action_function_name_7497(){
	// action...
}

Where the hook is called

In file: /templates/content-single-product.php
woocommerce_before_single_product
woocommerce/templates/content-single-product.php 27
do_action( 'woocommerce_before_single_product' );

Where in WP core the hook is used WooCommerce

woocommerce/includes/wc-template-hooks.php 306
add_action( 'woocommerce_before_single_product', 'woocommerce_output_all_notices', 10 );