phr. (context legal English) Something that has no owner, and not subject to jurisdiction of any state, susceptible to national appropriation.
Res nullius (lit: nobody's property) is a Latin term derived from Roman law whereby res (an object in the legal sense, anything that can be owned, even a slave, but not a subject in law such as a citizen) is not yet the object of rights of any specific subject. Such items are considered ownerless property and are usually free to be owned.
Examples of res nullius in the socio-economic sphere are wild animals or abandoned property. Finding can also be a means of occupation (i.e. vesting ownership), since a thing completely lost or abandoned is res nullius, and therefore belonged to the first taker. Specific legislation may be made, e.g. for beachcombing.