demarcation vs Rubicon

demarcation and Rubicon both are nouns.

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

As nouns, Rubicon is a hyponym of demarcation; that is, Rubicon is a word with a more specific, narrower meaning than demarcation:

demarcation: a conceptual separation or distinction
Rubicon: a line that when crossed permits of no return and typically results in irrevocable commitment

Other hyponyms of demarcation include point of no return.

demarcation (noun)	Rubicon (noun)
a conceptual separation or distinction	a line that when crossed permits of no return and typically results in irrevocable commitment
the boundary of a specific area	the boundary in ancient times between Italy and Gaul; Caesar's crossing it with his army in 49 BC was an act of war