A cognomen is something like an extra name given to a Roman citizen; it was something personal which functioned a bit like a nickname, but was typically passed from father to son.

姓氏就像给罗马公民额外名字；人名字，有点像昵，但通常父亲传给。

In 160 CE, Julia was born at Emesa, Syria and her cognomen, Domna, means " black" , which has to do with the sun god El-Gabal (Elagabalus) , whose cult stone was black.

公元 160 年，朱莉娅出生在叙利亚埃梅萨，她姓 Domna 意思“黑色”，与太阳神埃喇伽巴有关，他崇拜石黑色。