The paper summarizes two researches of applicability of the Czech Lexicon of mathematics focusing on two environments (technology-supported and CLIL) in secondary mathematics lessons. It gives a brief description of the process of development of the Czech Lexicon.
This description should help the reader understand the presented research. Attention is paid to those terms that are missing in the Lexicon but are needed for the description of the two selected types of lessons (technology-supported and CLIL).
The study shows that the Czech Lexicon, although constructed for teaching mathematics, can be used in other settings. The only terms that are missing are those that are specific for the particular area.
As the Czech Lexicon is an open system, they can be easily added. What is more, the missing terms point at those areas of these specific mathematics lessons that need more attention of the teacher as they use other activities and interactions than those used in a typical lesson of mathematics.