From Stamps of the World
The Channel Islands (Norman: Îles d'la Manche, French: Îles Anglo-Normandes or Îles de la Manche) are an archipelago in the English Channel, off the French coast of Normandy. They include two Crown dependencies: the Bailiwick of Jersey, consisting of Jersey, the largest of the islands; and the Bailiwick of Guernsey, consisting of Guernsey, Alderney, Sark and some smaller islands. They are considered the remnants of the Duchy of Normandy and, although they are not part of the United Kingdom, it is responsible for the defence and international relations of the islands. The Crown dependencies are not members of the Commonwealth of Nations or of the European Union. The two bailiwicks have been administered separately since the late 13th century; each has its own independent laws, elections, and representative bodies (although in modern times, politicians from the islands' legislatures are in regular contact). Any institution common to both is the exception rather than the rule. The Bailiwick of Guernsey is divided into three jurisdictions – Guernsey, Alderney and Sark – each with its own legislature.
The term "Channel Islands" began to be used around 1830, possibly first by the Royal Navy as a collective name for the islands.