natural philosophy vs center of buoyancy

natural philosophy and center of buoyancy both are nouns.

Word	Noun	Adjective	Verb	Adverb
natural philosophy	Yes	No	No	No
center of buoyancy	Yes	No	No	No

natural philosophy (noun)	center of buoyancy (noun)
the science of matter and energy and their interactions	(physics) the center of mass of the immersed part of ship or other floating object