wellhead vs rootage

wellhead and rootage both are nouns.

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

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

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

wellhead (noun)	rootage (noun)
a structure built over a well	the place where something begins, where it springs into being
the source of water for a well	a developed system of roots
	fixedness by or as if by roots