Any of several Protestant groups strongly influenced by Calvinism. They are often called by national names (Swiss Reformed, Dutch Reformed, etc.). The name was originally used by all the Protestant churches that arose out of the 16th-century Reformation but was later confined to the Calvinistic churches of continental Europe, most of which use a Presbyterian form of church government. The Calvinistic churches of the British Isles became known as Presbyterian churches (see Presbyterianism)