English English Wikipedia has an article on:British IslandsWikipedia Proper noun the British Islands The four polities of (i) the United Kingdom of Great Britain and Northern Ireland; (ii) the Bailiwick of Guernsey (including the jurisdictions of Alderney, Guernsey and Sark); (ii) the Bailiwick of Jersey; and (iv) the Isle of Man. Related terms British IslesWikiwand - on Seamless Wikipedia browsing. On steroids.