- The island of Great Britain during pre-Roman, Roman, and early Anglo-Saxon times before the reign of Alfred the Great (871–899). The name is derived from Britannia, which the Romans used for the portion of the island that they occupied.
- Abbr. Br. or Brit. See United Kingdom.
- The island of Great Britain, consisting of England, Scotland and Wales. [from 10th c.]
- (now historical) Brittany. [from 13th c.]
- (now historical) The United Kingdom; the British state and its dominions and holdings; the British Empire. [from 17th c.]
- (in the plural) The British Empire. [from 19th c.]
Old English Breoton, Bryten etc., from Latin Britannia; later reinforced by Anglo-Norman Britaine, Old French Bretaigne, from Latin Brittannia, variant of Britannia, from Britannī (see Etymology 2, below).
- (now rare, historical) An ancient Briton. [from 15th c.]
(comparative more Britain, superlative most Britain)