symbol vs dollar

symbol and dollar both are nouns.

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

As nouns, dollar is a hyponym of symbol; that is, dollar is a word with a more specific, narrower meaning than symbol:

symbol: an arbitrary sign (written or printed) that has acquired a conventional significance
dollar: a symbol of commercialism or greed

symbol (noun)	dollar (noun)
something visible that by association or convention represents something else that is invisible	a symbol of commercialism or greed
an arbitrary sign (written or printed) that has acquired a conventional significance	a piece of paper money worth one dollar
	a United States coin worth one dollar
	the basic monetary unit in many countries; equal to 100 cents