Charles's law vs law of nature

Charles's law and law of nature both are nouns.

Word	Noun	Adjective	Verb	Adverb
Charles's law	Yes	No	No	No
law of nature	Yes	No	No	No

As nouns, law of nature is a hypernym of Charles's law; that is, law of nature is a word with a broader meaning than Charles's law:

Charles's law: (physics) the density of an ideal gas at constant pressure varies inversely with the temperature
law of nature: a generalization that describes recurring facts or events in nature

Other hypernyms of Charles's law include law.

Charles's law (noun)	law of nature (noun)
(physics) the density of an ideal gas at constant pressure varies inversely with the temperature	a generalization that describes recurring facts or events in nature