facial index vs ratio

facial index and ratio both are nouns.

Word	Noun	Adjective	Verb	Adverb
facial index	Yes	No	No	No
ratio	Yes	No	No	No

As nouns, ratio is a hypernym of facial index; that is, ratio is a word with a broader meaning than facial index:

facial index: the ratio (in percent) of the maximum width to the maximum height of the face
ratio: the relative magnitudes of two quantities (usually expressed as a quotient)

facial index (noun)	ratio (noun)
the ratio (in percent) of the maximum width to the maximum height of the face	the relation between things (or parts of things) with respect to their comparative quantity, magnitude, or degree
	the relative magnitudes of two quantities (usually expressed as a quotient)