vitrification vs natural action

vitrification and natural action both are nouns.

Word	Noun	Adjective	Verb	Adverb
vitrification	Yes	No	No	No
natural action	Yes	No	No	No

As nouns, natural action is a hypernym of vitrification; that is, natural action is a word with a broader meaning than vitrification:

vitrification: the process of becoming vitreous
natural action: a process existing in or produced by nature (rather than by the intent of human beings)

Other hypernyms of vitrification include action, activity, natural process.

vitrification (noun)	natural action (noun)
the process of becoming vitreous	a process existing in or produced by nature (rather than by the intent of human beings)
a vitrified substance; the glassy result of being vitrified