The diploma thesis deals with the speech of sport commentaries and expressions used by sport commentators during sport broadcast. The thesis focuses on the lexicological level of their speech. The theoretical part at first presents a short summary of language of sport journalism and then the major part of the theoretical part is dedicated to meaning. Several different approaches to meaning are presented in this part as well as definition of meaning itself. Theoretical part also defines semantic change and it focuses on polysemy and homonymy and their distinction. The practical part is dedicated to the occurrence of polysemous and homonymous words among arbitrary chosen sport terms. The diploma thesis should contribute to the further study of the language of sport commentaries. The thesis should also be useful for the scientific and public society and it should serve as a link between those two areas.