representation of an entity from which the important elements have been abstracted by removing unimportant detail while at the same time retaining the interrelationship between the key elements of the whole

NOTE A model may be made more or less abstract by the successive suppression of detail such that the concepts and relationships come into enhanced focus and become more readily understood. However the process can be taken too far when the simplification has exceeded the threshold where a necessary understanding may be achieved. Thus the process of modelling is one of going only far enough to achieve the optimum understanding and insight — and no further.

NOTE A model is a way of representing something, other than in its natural state.