What is used to describe geographically and culturally Britain, Ireland, Scotland, Cornwall and Wales?

Scotland, Cornwall and Wales are all part of the island of Britain. And so is England, which you seem to have missed out. Scotland (in north Britain), Wales (in the west of Britain), and Cornwall (in the south-west of Britain) can all be described as Celtic - even though the term "Celtic" was a later invention. England (the country that takes up the south and east of the island of Britain) would not be described as Celtic. Its culture - and to an extent its ethnicity - are mainly Anglo-Saxon and Anglo-Scandinavian. The Irish can be called Celtic - although the protestants in the north would not describe themselves as such.  more