As it has been shown that object is class’s data type, from which instantiation took place. If we write, for example:
myBike is of type, MountainBike.
public MountainBike myBike = new MountainBike();
MountainBike get descended from Object & Bicycle. Hence, MountainBike is an object as well as a Bicycle. It is used when Object or Bicycle objects are called.
It is not necessary that reverse is true: Bicycle might be MountainBike, however