Properly understanding a psychopathological term requires knowledge of the disorder described, the contexts and concepts from which it was coined, and its modification over time. In the case of formal thought disorder, we describe its evolution from its incorporation into psychopathology for purely descriptive purposes and associated with the influence of associationism and the idea of a direct dependence between thought and language to the present day, in which the use of computational tools and hypotheses from linguistics have promoted its use as a diagnostic tool and prognostic marker, while simultaneously leading to the incorporation of new terminology.