The Ministry of Education of Chile defines in the NI 220 decree from 1998 the fundamental objectives and compulsory minimum contents for high school. This curricular innovation is carried out by means of the incorporation of the most recent advances in each discipline which, in case of the Castilian Language and Communication subsector, implies the opening of the curriculum to the textual and discursive levels of the study of language. For their part, the school texts must incorporate such contents to appropriately fulfil their role as facilitator of the learning in the classroom. Hence, it is valid to wonder about the quality of this integration from a strictly disciplinary perspective. This investigation focalizes on the treatment of public discourse, central content in Castilian Language and Communication in fourth grade in high school. Particularly, the definitions of public discourse proposed in five school texts from this subsector and level are analyzed and compared. As a result, a great heterogeneity among the definitions appearing in these texts was found, which evidences a lack of consolidation of certain linguistic-discursive contents. Based on the theoretical exploration, the analysis of the texts and the curricular framework, a new definition of public discourse is proposed.