The aim of the article is to perform a semantic and lexical analysis of the noun kacerz / kacerek appearing in the toponym Księży Kacerek. This is what the inhabitants of Wągrowiec, Greater Poland, call the green recreation area located in the centre of their city on the Wełna River. The name has approximately a hundred-year-old tradition. Dictionary data shows that in the 16th century, we are dealing with two separate referents and two separate lexemes of German origin: the noun kacerz referred to a person, while the noun kaszer ∥ kaserz referred to a tool. The analysis showed that in the standard language, starting from the Middle Polish period, the form kacerz / kacerek could refer both to a person (‘heretic’; a sequative name) and a fishing tool, which can be considered a manifestation of lexical homonymy conditioned by phonetic processes. In the dialects, in addition to the primary meaning associated with the aforementioned tool, a secondary meaning has developed that refers to a small swampy body of water.The aim of the article is to perform a semantic and lexical analysis of the noun kacerz / kacerek appearing in the toponym Księży Kacerek. This is what the inhabitants of Wągrowiec, Greater Poland, call the green recreation area located in the centre of their city on the Wełna River. The name has approximately a hundred-year-old tradition. Dictionary data shows that in the 16th century, we are dealing with two separate referents and two separate lexemes of German origin: the noun kacerz referred to a person, while the noun kaszer ∥ kaserz referred to a tool. The analysis showed that in the standard language, starting from the Middle Polish period, the form kacerz / kacerek could refer both to a person (‘heretic’; a sequative name) and a fishing tool, which can be considered a manifestation of lexical homonymy conditioned by phonetic processes. In the dialects, in addition to the primary meaning associated with the aforementioned tool, a secondary meaning has developed that refers to a small swampy body of water
