What is "charter colony"

Charter colony is one of the three classes of colonial government established in the 17th century English colonies in North America, the other classes being proprietary colony and royal colony. The colonies of Rhode Island, Connecticut, and Massachusetts Bay were charter colonies. In a charter colony, Britain granted a charter to the colonial government establishing the rules under which the colony was to be governed. The charters of Rhode Island and Connecticut granted the colonists significantly more political liberty than other colonies. Rhode Island and Connecticut continued to use their colonial charters as their State constitutions after the American Revolution.