Regiment or the Regimental system (Ukrainian: Полк, romanized: Polk, Ukrainian: Полковий устрій, romanized: Polkovyi ustriy) is a historical administrative, territorial, military and judicial unit of the country's subdivision of the Cossack Hetmanate and the Sloboda Ukraine in the XVII–XVIII centuries.[1]
System was expanded out of already existing system of the Registered Cossacks over Kyiv, Bratslav and Chernihiv Voivodeships in the Polish–Lithuanian Commonwealth.
Regiments were headed by the Cossack Colonel (Ukrainian: Полковник, romanized: Polkovnyk) who was a member of the Cossack Council of the Officers (Ukrainian: Рада Старшин, romanized: Rada Starshyn).