Cockney is a term commonly applied to people who are born within the sound of the bells of Bow Church, in Cheapside. College Of Surgeons. (royal). Lincoln's Inn Fields. very interesting to professional visitors. Nearest Railway Station, Temple (dis. ).
Cockney rhyming slang is a colloquial form of English slang originating from the East End of London.
Typically the common usage word to which the Cockney slang refers is replaced with the first word of a phrase that rhymes with that word.
For example "butchers" means "look" because "butcher's hook" rhymes with "look". Similarly "Cheryl" means "snow" (Cheryl Crow).
There are a number of exceptions to this rule however e.g. Cheese and Rice = Jesus Christ.