《礼记·曲礼下》
至于散处四夷的小诸侯，进入天子瓷内，自称曰 某国人 。在国外，自称曰 子 ；在国内，自称曰 孤 。
庶方小侯入天子之国，曰某人，于外曰子，自称曰孤。
As for the small vassals who lived dispersedly in the remote regions, they called themselves "People of a Certain Country" after they entered the imperial domain. In foreign countries, they called themselves "Son"; in their countries, they called themselves "Orphan".