Abstract
<jats:title>Abstract</jats:title> <jats:p> This chapter examines the role of usage labels in <jats:italic>Diccionario da Língua Portugueza</jats:italic> by António de Morais Silva, an eighteenth-century Portuguese dictionary first published in 1789. It illustrates how these labels — covering diachronic (temporal), diatopic (geographical), diastratic (social), diaphasic (contextual), and diatechnical (specialised knowledge) variations — helped to establish an organised approach to accessing social, cultural, and linguistic knowledge. The study applies contemporary metalexicographic frameworks to highlight Morais Silva’s categorisation of linguistic information and his representation of linguistic variation. The methodology involves a close analysis of the types, positioning, and function of usage labels, examining the challenges of encoding and consistency. Furthermore, it addresses issues such as label inconsistency and digital encoding, offering insights for future research on historical dictionaries. The study emphasises the cultural significance of usage labels and their role in the systematic organisation of knowledge. </jats:p>