demarcation line vs boundary

demarcation line and boundary both are nouns.

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

As nouns, boundary is a hypernym of demarcation line; that is, boundary is a word with a broader meaning than demarcation line:

Other hypernyms of demarcation line include bound, bounds.

demarcation line (noun)	boundary (noun)
the boundary of a specific area	the greatest possible degree of something
	the line or plane indicating the limit or extent of something
	a line determining the limits of an area