An object is a unit of the model of the environment.
The environment, which together with the subject constitutes psychic reality, is itself a model. It is neither identical with independent reality nor a copy of it. The psyche constructs this model from the knowledge generated by the psychic functions.
An object must therefore be distinguished from that which exists independently of the psyche. The object belongs to the model: it is an element of the environment generated by the psyche.
An object is perceived in time. It can preserve its identity while at the same time changing its state, participating in actions, and interacting with other objects. Knowledge of what remains invariant is generated by the function of perception of invariants (S), while knowledge of what changes is generated by the function of perception of changes (N).
An object can therefore be defined more fully as follows:
An object is a unit of the model of the environment represented in psychic reality as existing in time.
For a more detailed discussion of the concept of an object, its states, actions, interactions, and processes, see What Is an Object?.
For the distinction between subject and object and an earlier stage in the development of these concepts, see Subject and Object.