Briton
noun
Brit·on ˈbri-tᵊn 
1
: a member of one of the peoples inhabiting Britain prior to the Anglo-Saxon invasions
2
: a native or subject of Great Britain
especially : englishman
Word History
Etymology
Middle English Breton, from Middle French & Latin; Middle French, from Latin Britton-, Britto, of Celtic origin; akin to Welsh Brython
First Known Use
13th century, in the meaning defined at sense 1