Great Britain is the official name given to the two kingdoms of England and Scotland, and the principality of Wales. The United Kingdom (UK) includes these areas as well as Northern Ireland. Britain refers to only England and Wales, though some will shorten Great Britain with this term.
"British Sayings" I think it's cool how in South we use a lot of these. It's probably because this region is mostly of English decent, which also accounts for our accents. Okay, phonetics rant over. lol