Old English Bryttisc "of or relating to (ancient) Britons," from Bryttas "natives of ancient Britain" (see Briton). First modern record of British Isles is from 1620s.

coming from or having to do with the island of Great Britain.

American Web Dictionaries

Pertaining to something or someone from Great Britain. Many British people emigrated to the Americas, Africa, Australia, and New Zealand.

In the early days of bicycle manufacture, every industrialized country had its own system of thread sizes and standard dimensions for bicycle parts. The British system is the one that has, by-and-larg [..]

Refers to those living in Britain or those who have British citizenship. The majority of the population in Northern Ireland, mainly those who are Protestant and Unionist, consider themselves to be British. See also: Britain

(n) the people of Great Britain(adj) of or relating to or characteristic of Great Britain or its people or culture

With ''the'', the citizens or inhabitants of Britain collectively. With ''the'', the citizens or inhabitants of the United Kingdom collectively. (history) The ancient inhabitants of the southern [..]

typically British ''Il est très british'' - he is a very typical Brit.

The British language is the Brythonic Celtic language that was spoken in Britain before the Anglo-Saxon invasions.