demarcation vs boundary

demarcation and boundary both are nouns.

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

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

Other hypernyms of demarcation include bound, bounds.

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