In every field of the law, one will come across terms of the art that are related to one another and build upon one another in ways which are not quite clear. One such cluster in international law is comprised of “territory,” “title,” “sovereignty,” “jurisdiction” and “statehood.” Another one, in citizenship and immigration law, consists of “nationality,” “citizenship,” “domicile,” “residence,” “status” and “rights of entry.” The concepts within a cluster are all related to one another, but not in any straightforward logical relationship. They can be synonyms, overlapping concepts, distinct concepts and subordinate to one another. I shall use the phenomenon of clustered concepts to look at what definitions in law mean, and how many ways there are both to define concepts and to evade definitions in legislation as well as judicial practice. My presentation focuses on the strategic payoffs of substituting enumerations and procedures for definitions, and introducing even newer concepts.