Megamodelling and Etymology

Is a model of a model, a metamodel? Is the relational model a metamodel? Is it a model? What is a component metamodel? Is it a model of a component model? The word MODEL is subject to a lot of debates in Model Driven Engineering. Add the notion of metamodel on top of it and you will just enter what some people call the Meta-muddle. Recently megamodels have been proposed to avoid the meta-muddle. This approach is very promising but it does not solve however the primary problem. That is, even a simple use of the word Model could lead to misunderstanding and confusion. This paper tackles this problem from its very source: the polysemic nature of the word MODEL. The evolution and semantic variations of the word MODEL are modelled from many different perspectives. This papers tells how the prefix MED in indo-european has lead, five millenniums after, to the acronym MDE, and this via the word MODEL. Based on an extensive study of encyclopedias, dictionaries, thesauri, and etymological sources, it is shown that the many senses of the word MODEL can be clustered into four groups, namely model-as-representation, model-as-example, model-as-type, and model-as-mold. All these groups are fundamental to understand the real nature of Model Driven Engineering. Megamodels and Etymology are indeed keys to avoid the Meta-muddle.on.