A more thorough explanation:

Definition: Caput mortuum is an archaic term that refers to a matter or thing that is void as to all persons and for all purposes.

Example: A property that has been abandoned for many years and has no legal owner is considered caput mortuum.

Explanation: In this example, the abandoned property has no legal owner and is therefore considered void as to all persons and for all purposes. It cannot be sold, rented, or used for any other purpose until a legal owner is established.