phlebogram vs X-ray

phlebogram and X-ray both are nouns.

Word	Noun	Adjective	Verb	Adverb
phlebogram	Yes	No	No	No
X-ray	Yes	No	No	No

As nouns, X-ray is a hypernym of phlebogram; that is, X-ray is a word with a broader meaning than phlebogram:

phlebogram: an X ray of a vein injected with a radiopaque contrast medium
X-ray: a radiogram made by exposing photographic film to X rays; used in medical diagnosis

Other hypernyms of phlebogram include roentgenogram, X-ray photograph, X-ray picture, X ray.

phlebogram (noun)	X-ray (noun)
an X ray of a vein injected with a radiopaque contrast medium	a radiogram made by exposing photographic film to X rays; used in medical diagnosis
	electromagnetic radiation of short wavelength produced when high-speed electrons strike a solid target