X-ray film vs bitewing

X-ray film and bitewing both are nouns.

Word	Noun	Adjective	Verb	Adverb
X-ray film	Yes	No	No	No
bitewing	Yes	No	No	No

As nouns, bitewing is a hyponym of X-ray film; that is, bitewing is a word with a more specific, narrower meaning than X-ray film:

X-ray film: photographic film used to make X-ray pictures
bitewing: a dental X-ray film that can be held in place by the teeth during radiography

X-ray film (noun)	bitewing (noun)
photographic film used to make X-ray pictures	a dental X-ray film that can be held in place by the teeth during radiography