There is an interesting difference between the name of one of the building blocks of logic in English, Czech and Polish. While there is a propositional calculus in English, Czech logicians investigate a subject ‘výrokový kalkul’ instead and Polish logicians delve into ‘rachunek zdań’. Since Frege, propositions have retained an extensive philosophical background. Czech ‘výroky’ contained a more modest philosophical background. They are linked with the act of stating. Thus, Czech logicians deal with a ‘calculus of statements’. In contrast, the term ‘zdanie’ could be translated as ‘sentence’ and consequently the Polish ‘rachunek zdań’ as a ‘sentential calculus’. My talk will focus on how this approach in Polish terminology appeared.Peter Simons argues that it was Jan Łukasiewicz who introduced this terminology, and that the terminology was a part of Łukasiewicz’s denial of psychologism. As Łukasiewicz was an important scholar in the Lvov-Warsaw School and the School influenced considerably a logical scene in Poland, Łukasiewicz’s terminology spread in Polish logic. I would like to take a closer look at how the term for propositions was settled in Polish logic and the discussions that concerned it. To illustrate the atmosphere in which Łukasiewicz’s terminology was formulated, the talk will present firstly the terminology used in then logical works and translations. The second section introduces the views of Kazimierz Twardowski, the founder of the Lvov-Warsaw School. After a presentation of Łukasiewicz’s views, the final part of my talk will concern other terminological views in the Lvov-Warsaw School.