What's the meaning of the phrase 'Crown jewels'?
Literally, the Crown Jewels are the state jewellery of the United Kingdom. In a figurative sense 'the crown jewels' is a slang term for the male genitalia.
What's the origin of the phrase 'Crown jewels'?
Since the 17th century the state jewellery of the United Kingdom, which is carried or worn by the monarch on state occasions, has been known as the Crown Jewels.
They were referred to as such by Edward Bowles in his text The Mysterie of Iniquitie, 1643:
Let the Queen finde a pretence to goe into Holland, (taking with her the Crowne Jewells, which were pawned or sold).
The expression is now more widely used to refer to the pinnacle of quality in all manner of fields. For example, the four golf major tournaments might be called 'the crown jewels of golf', etc.
It might be expected that the slang expression 'the crown jewels', referring to the male genitals, came from the UK too but, in fact, it doesn't.
It is first found in the USA in the 1970s, which not as early as one might imagine. Its definition was recorded in 1970 in the linguistic quarterly magazine American Speech:
Crown jewels, male genitals.
The phrase derives from an earlier expression, also American, that is, 'the family jewels', which has just the same meaning. This was put into print in about half a century earlier by H. N. Cary in Sexual Vocabulary, 1920:
Family jewels, the penis and testes.
See also: the dog's bollocks.