babygram vs roentgenogram

babygram and roentgenogram both are nouns.

Word	Noun	Adjective	Verb	Adverb
babygram	Yes	No	No	No
roentgenogram	Yes	No	No	No

As nouns, roentgenogram is a hypernym of babygram; that is, roentgenogram is a word with a broader meaning than babygram:

babygram: an X-ray of the entire body of an infant.
roentgenogram: a radiogram made by exposing photographic film to X rays; used in medical diagnosis

Other hypernyms of babygram include X-ray, X-ray photograph, X-ray picture, X ray.

babygram (noun)	roentgenogram (noun)
an X-ray of the entire body of an infant.	a radiogram made by exposing photographic film to X rays; used in medical diagnosis