Crown vs symbol

Crown and symbol both are nouns.

Word	Noun	Adjective	Verb	Adverb
Crown	Yes	No	No	No
symbol	Yes	No	No	No

As nouns, symbol is a hypernym of Crown; that is, symbol is a word with a broader meaning than Crown:

Crown: the Crown (or the reigning monarch) as the symbol of the power and authority of a monarchy
symbol: an arbitrary sign (written or printed) that has acquired a conventional significance

Crown (noun)	symbol (noun)
the Crown (or the reigning monarch) as the symbol of the power and authority of a monarchy	something visible that by association or convention represents something else that is invisible
	an arbitrary sign (written or printed) that has acquired a conventional significance