Regiment or the regimental system (Ukrainian: полк, romanized: polk, Ukrainian: полковий устрій, romanized: polkovyi ustrii) is a historical administrative, territorial, military and judicial unit of the country's subdivision of the Cossack Hetmanate and the Sloboda Ukraine in the 17th–18th 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).