drag coefficient vs coefficient of drag

drag coefficient and coefficient of drag both are nouns.

Word	Noun	Adjective	Verb	Adverb
drag coefficient	Yes	No	No	No
coefficient of drag	Yes	No	No	No

As nouns, drag coefficient and coefficient of drag are synonyms defined as:

drag coefficient and coefficient of drag: the ratio of the drag on a body moving through air to the product of the velocity and the surface area of the body

drag coefficient (noun)	coefficient of drag (noun)
the ratio of the drag on a body moving through air to the product of the velocity and the surface area of the body	the ratio of the drag on a body moving through air to the product of the velocity and the surface area of the body