Regiment () is a historical administrative, territorial, military and judicial unit of subdivision in the Cossack Hetmanate and the Sloboda Ukraine in the 17thâÂÂ18th centuries.
System was expanded out of already existing system of the Registered Cossacks over Kyiv, Bratslav and Chernihiv Voivodeships in the PolishâÂÂLithuanian Commonwealth.
Regiments were headed by the Cossack Colonel () who was a member of the Cossack Council of the Officers ().
Regiment was the first level of the administrative and military division of the Cossack Hetmanate.
In 1649, when the Cossack Hetmanate was established by the Treaty of Zboriv and controlled both the right and left banks, it included 16 regiments. After the loss of the RightâÂÂBank Ukraine, a number was reduced to 10 regiments.