fountainhead vs rootage

fountainhead and rootage both are nouns.

Word	Noun	Adjective	Verb	Adverb
fountainhead	Yes	No	No	No
rootage	Yes	No	No	No

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

Other hypernyms of fountainhead include beginning, origin, root, source.

fountainhead (noun)	rootage (noun)
an abundant source	the place where something begins, where it springs into being
the source of water from which a stream arises	a developed system of roots
	fixedness by or as if by roots