With over 100 slang phrases, Cockney Rhyming Slang action gives you a random slang phrase and the definition every time you ask. Cockney Rhyming Slang originates from the East End of London back in the 1840's, it was widely adopted by market traders, costermongers, and other street sellers. Although it's not so widely used today, it is an important part of London and indeed British history.