definition
strict definition
virtual object
An abstract object whose existence and/or defining parameters are not visible in the real world.
A virtual object is an abstract or conceptual object which either exists independently of space, or which is an abstraction of space and cannot be discerned visibly in the real world.
The object has a conceptual identity rather than a directly visible physical form. It can concern space without being a visible part of that space.
A property listing is a notice about the availability of land or constructed space. The notice and the physical property have distinct identities.