English as a foreign language is no longer the sole object of specialized language classes, but increasingly a medium of university-level instruction in a range of content areas. This leads to a complex interaction between new academic content and the means of expressing this expertise through appropriate disciplinary language uses. Conceptually, this study focuses on oral disciplinary-reasoning episodes, in which knowledge structures are explicitly developed. These episodes exemplify diverse ways whereby disciplinary meaning making is co-constructed in English-medium instruction (EMI), with one specific type being language-related episodes which clarify specific items of terminology. Drawing on INTE-R-LICA, an international and interdisciplinary project, the database under investigation covers 671 minutes (67,605 words) of classroom discourse from a Spanish business administration degree programme. Findings suggest a structural diversity within these episodes, which are jointly constructed, and involve a rich variety of discursive strategies to effectuate meaning making. Our results indicate that an understanding of the crucial role of language in this disciplinary meaning-making process is essential for the TESOL profession to remain relevant in the current English language teaching educational landscape. In addition to providing expert input into the potential of a language-sensitive EMI pedagogy, TESOL teacher education will need to foster both language and content teachers' awareness of the disciplinary nature of classroom discourse and its role in developing subject expertise among their students.