What does it mean for southerners to call northerners bosses?

This is what big brother means. A courtesy title for you. Boss: Generally speaking, it's a colloquial title of Guangdong and Zhejiang.

I'm from the north, too, but I often go to the south to buy goods.

Every time I go to the south, the locals call me boss. At first, I didn't understand. I feel particularly embarrassed. How did I become your boss?

Because in the eyes of us northerners, the boss is the oldest person among brothers and sisters. My brother and sister can call me that, but outsiders can't call me boss in general.

Later, I learned that in the eyes of southerners, boss is a colloquial title, meaning big brother, boss.