dividing line vs demarcation

dividing line and demarcation both are nouns.

Word	Noun	Adjective	Verb	Adverb
dividing line	Yes	No	No	No
demarcation	Yes	No	No	No

As nouns, dividing line and demarcation are synonyms defined as:

Other synonyms of dividing line include contrast, line.

dividing line (noun)	demarcation (noun)
a conceptual separation or distinction	a conceptual separation or distinction
	the boundary of a specific area