SummaryThe following paper presents an analysis of the term ‘oppidum’, discussing its value for understanding social complexity in Iron Age Europe. Throughout this paper, the most relevant debates regarding the oppida and their value are synthesized from a semiotic point of view. Key features such as urban planning, social hierarchies and political centralization are analysed to frame research in terms of Iron Age mentalities and cultural diversity. Accordingly, the ‘oppidum’ is assessed as a conceptual tool, weighing its appropriateness as a wide‐ranging concept in the European Iron Age. Several criteria, such as urban planning, the role of memory or religion, and the creation of large public and assembly places, among others, are explored as proxies of social legitimation. These key aspects aim to define some traits to set the oppidum as a useful and organic archaeological term without undermining cultural specificities.