"-sn" is the surname, which is the user's last name or family name.

“- sn”是姓，这是用户的姓。

youdao

So, if a father's family name is Zhou, and the mother, Zhu, the baby could have four options for the surname: Zhou, Zhu, Zhouzhu or Zhuzhou.

如果爸爸姓周，妈妈姓朱，那么孩子的姓可以有四种选择：周、朱、周朱或朱周。

youdao

I: How do you spell your surname (or family name or last name)?

I：你的姓怎样拼？

youdao

But the Sir always goes with his first name: never with his family or surname.

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