(A) The actual exercise or enjoyment of any right or property. It is particularly used of franchises. Adverse user. An adverse user is such a use of the property as the owner himself would make, asking no permission, and disregarding all other claims to it, so far as they conflict with this use. (B) A person who uses or operates something, such as a computer, a machine or a member of a website forum.
USER
TheLaw.com Law Dictionary & Black's Law Dictionary 2nd Ed.