state boundary vs delimitation

state boundary and delimitation both are nouns.

Word	Noun	Adjective	Verb	Adverb
state boundary	Yes	No	No	No
delimitation	Yes	No	No	No

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

Other hypernyms of state boundary include border, borderline, boundary line, mete.

state boundary (noun)	delimitation (noun)
the boundary between two states	a line that indicates a boundary