An object is a resource in ENIGMA. It consists of events that execute actions and code. It is the basis of ENIGMA's logic and that is where the scripting itself is taking place. Objects usually have a sprite attached to them so its possible to see them. Everything in a game consists of objects, or more precisely, instances of objects. So an instance represents one particular instance, while objects represent all of the instances of the particular object.
Its equivalent in C++ would be classes.