Dictionary.net

When the American colonies were founded, "Governor" was used in two senses in England,-to denote the commander of a fortified post, like Hull or Tangier, and to denote the head of a great trading corporation, like the East India Company or the Massachusetts Company. The Governor of an American colony got his name by derivation from both these sources, probably. When the Revolution broke out and the royal Governors fled, the new State Constitutions usually made provision for a single executive, called the Governor. At first he was chosen by the Legislatures in most States south of New York, but now by the people. In the colonial period, the Governors of Rhode Island, of Connecticut, and of Massachusetts down to 1691, were chosen by the people; those of proprietary colonies by the proprietors; those of royal colonies by the crown.