This is the 7689th most frequent Polish word.
lucjusz
Lucjusz: A European fish species, also known as pike (Esox lucius).
The word 'Lucjusz' here refers to a proper name of a character in literature.
Lucjusz jest bohaterem powieści Apulejusza.
Lucius is the protagonist of Apuleius's novel.
The word 'lucjusz' is used here as a noun referring to the fish species 'pike'.
Ryba lucjusz żyje w czystych wodach polskich jezior.
The fish called pike lives in the clean waters of Polish lakes.
In this sentence, 'Lucjusz' is used as a proper name referring to a historical or religious figure.