一声姐妹大过天不叫姐妹叫女王
[yī shēng jiĕ mèi dà guò tiān bù jiào jiĕ mèi jiào nǚ wáng]
Meaning 'sisters before everything else—if not called sister then she is the queen,' the nickname portrays an endearing and slightly exaggerated sense of closeness and sisterhood between two people, implying that even if not sisters by blood, they treat each other like royalty in terms of affection and loyalty.