Shipping marks actually refer to labels, trademarks and signs. In Cantonese, many words are transliterated in English, and this word is transliterated from English MARK. So this word is actually a unique word in Cantonese dialect. If you are in Guangdong, you will often see words such as "Phoenix Ball Label" and "Chicken Bird Label", which actually means "Phoenix Ball Label" and "Chicken Bird Label".