The discovery of Priscian’s Institutiones Grammaticae brought a new perspective to the grammatical analysis of the eighth and ninth centuries, as it heavily relied on the commentaries on Donatus’s Ars Minor and Ars Maior, and many scholars of the time were not entirely aware of Priscian’s contribution to the scholarly discussion within the didactical framework. Entwining Priscian’s interest in metalanguage and definitions into their studies, scholars brought the methods of dialectics into the study of grammar. As such, we refer to a few relevant figures within the medieval framework who played a relevant role. Between the eighth and ninth centuries, scholars such as Alcuin of York started to determine a theory of definitions rooted in dialectics by observing and commenting on the use of definitions in Donatus and Priscian. This is also the case of the glosses and lexica written in the Middle Ages that shed light both on the need for definitions and on the relationship between Latin metalinguistic definitions and Germanic languages. Among the works concerned with metalanguage, the glosses from St. Gall hold a special place. The teaching methods used in the Abbey of St. Gall survive in the translations and commentaries of the monk, scholar, and teacher Notker Labeo, whose didactic purpose is evident in his work.