noun

1. territory under one government or ruler; dominion
2. land belonging to one person; estate
3. supreme ownership
4. field or sphere of activity or influence the domain of science
5. Comput. domain name
6. Math.
   1. the set of those values of an independent variable which exist for a given function
   2. the set of all integers, or a set of elements which can be combined in the same way as the integers
7. Physics a region in a ferromagnetic material within which the atoms are magnetically aligned: alignment of these regions results in the material being magnetized

Etymology: ME domein < MFr domaine < L dominium, right of ownership, dominion < dominus, a lord: see dominate