A group of islands lying off the coast of north-western Europe, from which they are separated by the North Sea and the English Channel. They include Britain, Ireland, the Isle of Man, the Isle of Wight, the Hebrides, the Orkney Islands, the Shetland Islands, the Scilly Isles, and the Channel Islands.
Definition of British Isles in US English:
British Isles
proper nounˈˌbridiSH ˈīlz
A group of islands lying off the coast of northwestern Europe, from which they are separated by the North Sea and the English Channel. They include Britain, Ireland, the Isle of Man, the Isle of Wight, the Hebrides, the Orkney Islands, the Shetland Islands, the Scilly Isles, and the Channel Islands.