BRITAIN

Britain

The term "Britain" is a linguistic descendant of one of the oldest known names for the island currently referred to as Great Britain. The terms Briton, British and British Isles, similarly derived, refer to its inhabitants and the smaller islands in the vicinity. Britain is the only ancient name for these islands to survive in general usage. Its first written appearance was by Pytheas of Massalia in the 4th century BCE. It originates with a group of P-Celtic speakers, resident on the island, who referred to themselves by the earliest known form of the term British.

The above text is a snippet from Wikipedia: Britain (placename)
and as such is available under the Creative Commons Attribution/Share-Alike License.

Need help with a clue?
Try your search in the crossword dictionary!