point of departure vs rootage

point of departure and rootage both are nouns.

Word	Noun	Adjective	Verb	Adverb
point of departure	Yes	No	No	No
rootage	Yes	No	No	No

As nouns, rootage is a hypernym of point of departure; that is, rootage is a word with a broader meaning than point of departure:

point of departure: a place from which an enterprise or expedition is launched
rootage: the place where something begins, where it springs into being

Other hypernyms of point of departure include beginning, origin, root, source.

point of departure (noun)	rootage (noun)
a beginning from which an enterprise is launched	the place where something begins, where it springs into being
a place from which an enterprise or expedition is launched	a developed system of roots
	fixedness by or as if by roots