Kozieł is a Polish surname, a variant of Kozioł. The root name, Kozioł, means "male goat" in Polish and was likely an occupational surname for a goatherd. The spelling difference results from regional Polish dialectal variation, where the underlying 'ó' mutates to 'ie' in certain areas. Despite being a variant, Kozieł also has a geographical counterpart in Poland, as noted by a village named Kozieł in Gmina Praszka, Opole Voivodeship, though the surname likely predates this village. The surname relates to cognates in other Slavic languages: Kozel in Czech, Kozlov in Russian, and Belarusian forms Kazloŭ, Kazlova, and Kazlow, reflecting a pan-Slavic onomastic trend.
Etymology
The element kozioł derives from Proto-Slavic *kozьlъ, meaning "he-goat." The association with the animal likely originated as a nickname for someone who exhibited goat-like characteristics (e.g., stubbornness, agility, or goatherding) and later became fixed as a hereditary surname. The variant form with ie (Kozieł) is characteristic of Lesser Polish dialects, while Kozioł prevails in standard Polish and other regions.
Sources: Wikipedia — Kozieł