n.

1. 领土，领地；领土权
   The conspirators were banished from the king's domain.

   阴谋家们被赶出了国王的领土。

2. （政府或私人的）所有地，地产
3. 领域，范围
   I can't answer your question about photography. It's not in my domain.

   我无法回答你有关摄影的问题。我不做那一行。

4. 地区，区域
5. 【数】域；定义域
6. 【物】（磁）畴

n.

1. an area owned or controlled by a ruler or government.
   ▸a sphere of activity or knowledge.
2. Computing  a distinct subset of the Internet with addresses sharing a common suffix.
3. Mathematics  the possible values of the independent variable or variables of a function.
4. Physics  a discrete region of magnetism in ferromagnetic material.
5. Biochemistry  a distinct region of a complex molecule or structure.