Legal terms have a special status at the interface between language and law. Adopting the general framework developed by Jackendoff and the concepts competence and performance as developed by Chomsky, it is shown that legal terms cannot be fully accounted for unless we set up a category of abstract objects. This idea corresponds largely to the classical view of terminology, which has been confronted with some challenges recently. It is shown that for legal terms, arguments against abstract objects are not pertinent. As abstract objects are not natural, it is important to consider their creation. Two types of creation are distinguished and illustrated, one for new concepts and one for terms corresponding to existing general language concepts. In the latter case, it is important for the abstract object to remain close enough to the intuitive prototype. At the same time, legal terms as abstract objects are shown to have a natural place in relation to legal theory.