symbol vs dollar mark

symbol and dollar mark both are nouns.

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

As nouns, dollar mark is a hyponym of symbol; that is, dollar mark 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 mark: a symbol of commercialism or greed

symbol (noun)	dollar mark (noun)
something visible that by association or convention represents something else that is invisible	a mark ($) written before a number to indicate that it stands for the number of dollars
an arbitrary sign (written or printed) that has acquired a conventional significance	a symbol of commercialism or greed