domain

Concise Oxford English Dictionary © 2008 Oxford University Press:
domain /də(ʊ)ˈmeɪn/

▶noun

• 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.

– derivatives
domanial /dəˈmeɪnɪəl/ adjective.

– origin ME: from Fr. domaine, alt. (by assoc. with L. dominus ‘lord’) of OFr. demeine (see demesne).