This article provides an account of the concepts of modernidad and modernismo in the Spanish language, chiefly in Spain, from the end of the eighteenth century to the beginning of the twentieth century. This account also reflects the peculiarities of how conceptual history is being conducted in Spain, which resulted in the recently published Diccionario de Conceptos Políticos y Sociales del Siglo xix Español. The authors conclude that an examination of these two terms reveals that the emphasis upon Spanish singularity has been exaggerated and that, despite the presumed historical backwardness of the country, Spain played an outstanding role in the creation of the language of modernity and postmodernity.