domain
Pronunciation:
/dəʊˈmeɪn//doʊˈmeɪn/noun
Definitions
A geographic area owned or controlled by a single person or organization.
Example: The king ruled his domain harshly.
A field or sphere of activity, influence or expertise.
Example: Dealing with complaints isn't really my domain: get in touch with customer services.
A group of related items, topics, or subjects.
The set of all possible mathematical entities (points) where a given function is defined.