marking vs grading

marking and grading both are nouns.

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

As nouns, marking and grading are synonyms defined as:

marking and grading: evaluation of performance by assigning a grade or score

Other synonyms of marking include scoring.

marking (noun)	grading (noun)
evaluation of performance by assigning a grade or score	the act of arranging in a graduated series
the act of making a visible mark on a surface	evaluation of performance by assigning a grade or score
a pattern of marks	changing the ground level to a smooth horizontal or gently sloping surface
a distinguishing symbol