Ataman
Ataman (variants: Otaman,Wataman, Vataman; Russian: атаман, Ukrainian: Отаман) was a title of Cossack and haidamak leaders of various kinds. In the Russian Empire, the term was the official title of the supreme military commanders of the Cossack armies. The Ukrainian version of the same word is Hetman. Otaman in Ukrainian Cossack forces was a position of a lower rank.
Etymology
The etymology of the word ataman/hetman is disputed. There may be several independent Germanic and Turkic origins for seemingly cognate forms of the word, all referring to the same concept. The hetman form may derive from the German Hauptmann by the way of Polish, like several other titles. The ataman form is more probably of Turkic origin, literally meaning "father of horsemen". During certain periods, broadly corresponding with involvement with the Polish-Lithuanian or Polish-Lithuanian-Ruthenian Commonwealth, the supreme leader of Ukrainian Cossacks was called Hetman. The ataman form is more commonly found in Russian periods, and exists in modern Russian, Turkish and Tatar. Also see Hetman: Etymology.