Form of headwear, symbolizing the power of a ruler
A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, particularly in Commonwealth countries, as an abstract name for the monarchy itself (and, by extension, the state of which said monarch is head) as distinct from the individual who inhabits it (that is, The Crown). A specific type of crown (or coronet for lower ranks of peerage) is employed in heraldry under strict rules.
https://en.wikipedia.org/wiki/Crown