A fork of Rural Dictionary
This has been defined elsewhere, correctly, as British slang for "the best". The interesting thing about its possible origin is that the word cynosure, meaning "something brilliant that attracts attention" derives from two Greek words, Kynos (meaning "dog's" or "of the dog") + oura (meaning "tail"). This meaning of "the dog's tail" was used at one time to refer to the constellation Ursa Minor, which is bright and attracts attention. So: did some classically-versed wag originate the phrase?
"My new video card is the dog's bollocks"