'ataman' originates from Russian, specifically the word 'атаман', which in turn derives from Turkic sources (compare Crimean Tatar 'otaman'/'ataman'); the element 'ata' in Turkic meant 'father' or 'ancestor' and was used as a respectful term for a leader.

'ataman' passed into English from Russian (and via other East European usages such as Polish or Ukrainian); Old Turkic/Crimean Tatar forms like 'otaman' influenced East Slavic usage, producing Russian 'атаман', which became the modern English 'ataman'.

Initially the root element conveyed 'father' or 'ancestor' (a term of respect); over time it came to denote a specific title for Cossack commanders and then more generally 'chief' or 'leader' in English.