natural philosophy vs metric function

natural philosophy and metric function both are nouns.

Word	Noun	Adjective	Verb	Adverb
natural philosophy	Yes	No	No	No
metric function	Yes	No	No	No

natural philosophy (noun)	metric function (noun)
the science of matter and energy and their interactions	a function of a topological space that gives, for any two points in the space, a value equal to the distance between them