- (geography) A group of islands off the northwest coast of mainland Europe, including Great Britain, Ireland, the Isle of Wight, the Isles of Scilly, the Isle of Man, the Outer Hebrides, the Inner Hebrides, the Orkney Islands, the Shetland Islands and many other smaller islands. Use may include the Channel Islands, although these are physically closer to mainland Europe.
The term is sometimes seen as politically outdated, particularly in relation to Ireland, because the majority of Ireland is no longer (since 1922) part of the United Kingdom of Great Britain and Northern Ireland. However, the political union of Great Britain derives its name from the land mass (i.e. the British Isles), rather than the other way round. The Romans named the islands "Britannia" and its inhabitants "Britons" in the 1st century BC, more than a millennium before the political union of Great Britain was conceived.