Britain /ˈbɹɪt.ən/adjective 1noun 2forms 3phrases 1 adjective1 •(no longer used) Briton; British.[M]ightie Albion, father of the bold / And warlike people which the Britaine Islands hold. — 1596 noun2 •The United Kingdom, a kingdom and country in Northern Europe including the island of Great Britain as well as Northern Ireland on the northeastern portion of the island of Ireland. •(no longer used, historical) An ancient Briton.The Britains’ struggles with the Scots and Picts [...] led to the Britains asking the Romans for help in constructing a great wall. — 2002 formsBritains · more Britain · most Britain Phrases with Britain for BritainVery well or for a long time.