Britannia

n. United Kingdom (Britain and Northern Ireland); Great Britain (England, Scotland and Wales); ancient Roman name for the island of Great Britain

The Britannias was the original Latin name the Roman Empire gave to the British Isles, consisting of Albion, Hibernia and many smaller islands, originating from a reference from Pytheas of Massilia (Marseilles) in around 300 BC to the Pretanic (or Britannic) Islands. Deriving from Pretannia, Diodorus's Greek rendering of the indigenous name pretani, Britannia became the preferred Roman term for the island of Great Britain, and in particular the Roman province of Britain which extended north as far as Hadrian's Wall. Britannia was personified as a Goddess by the Romans, and in more recent times has become a figure of national personification of the United Kingdom.
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n. Britannia, ancient Roman name for the island of Great Britain

(n.)
A white-metal alloy of tin, antimony, bismuth, copper, etc. It somewhat resembles silver, and is used for table ware. Called also Britannia metal.
  

[Celtic] A Romano-Celtic (British) tutelary goddess.