The purpose of this paper is to analyze the presence and theconsistency of criteria in the Glossary of the Cantigas de SantaMaria, edited by Walter Mettmann in 1972. The Cantigas, compiledin the end of the thirteenth century by Afonso X and hiscollaborators from Toledo, are one of the most extensive collectionsof poetry, iconography and music in Medieval Portuguese.Cambraia (2000) and Cunha (1966) were taken into account, dueto their regularity and meticulousness. Emphasis was given to theanalysis on the way the author deals with the extent of theGlossary, the constitution of its articles and the idiomaticexpressions. The absence of explicit norms to elaborate theGlossary is a serious deficiency of this edition, forcing its readerto deduce these norms. It is not our intention to find solutions toall the omissions found in the Glossary, but to point out a bodyof clear and coherent norms.