marking vs symbol

marking and symbol both are nouns.

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

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

marking: a distinguishing symbol
symbol: an arbitrary sign (written or printed) that has acquired a conventional significance

marking (noun)	symbol (noun)
evaluation of performance by assigning a grade or score	something visible that by association or convention represents something else that is invisible
the act of making a visible mark on a surface	an arbitrary sign (written or printed) that has acquired a conventional significance
a pattern of marks
a distinguishing symbol