Cockney rhyming slang is one of the more fascinating forms of slang I’m familiar with, because there’s a total disconnection between the word used and the word meant, and you have to know the original phrase that made the connection. There’s really very little way to divine the meaning without prior knowledge. It’s all so… arbitrary.

The basic structure of rhyming slang is finding a short sentence that rhyme the word you’re trying to say. A common example is “apples and pairs” for “stairs”. The fun part is that you rarely use the full phrase in place of a single word, you usually just use the first word of the phrase. So for “stairs”, you would simply say “apples”. There are examples ranging from the 19th century (“feet” being “plates” – of meat) to modern day usages (“Britneys” for “beers”).

The most interesting bits are when usages of rhyming slang cross over to general slang usage, especially when they lose their etymology. “Berk”, a common slang term for an idiot, is not perceived to be particularly offensive because most people don’t realize it derives from the rhyming slang “Berkeley Hunt”, whose rhyme I shall leave up to your collective imaginations.