关于“兄弟”的不同叫法

brother-in-law: 小舅子/小叔子

connected by marriage.

e.g. You got married to someone and he/she had a brother. That’s your brother-in-law.

half-brother: 同父异母兄弟；同母异父兄弟

Your dad got remarried and had a son. That’s your half-brother.

step brother: 继兄弟

the son of the person that your parent married.

adopted brother: 收养的兄弟

When your parents legally adopt somebody else. They become your brother.