Cockney rhyming slang is a form of English slang which originated in the East End of London. Many of its expressions have passed into common language, and the creation of new ones is no longer restricted to Cockneys.
Rhyming slang developed as a way of obscuring the meaning of sentences to those who did not
understand the slang, though it remains a matter of speculation whether this was a linguistic accident, or whether it was developed intentionally to assist criminals or to maintain a
particular community.
Rhyming slang works by replacing the word to be obscured with the first word of a phrase that rhymes with that word. For instance, "face" would be replaced by "boat", because face rhymes with "boat race". Similarly "feet" becomes "plates" ("plates of meat"), and "money" is "bread" (a very common usage, from "bread and honey"). Sometimes the full phrase is
used, for example "Currant Bun" to mean "The Sun" (often referring to the
British Tabloid Newspaper of that name). There is no hard and fast rule for this, and you just have to know whether a particular expression is always shortened, never shortened, or can be used either way.
