skiagraph vs skiagram

skiagraph and skiagram both are nouns.

Word	Noun	Adjective	Verb	Adverb
skiagraph	Yes	No	No	No
skiagram	Yes	No	No	No

As nouns, skiagraph and skiagram are synonyms defined as:

skiagraph and skiagram: a photographic image produced on a radiosensitive surface by radiation other than visible light (especially by X-rays or gamma rays)

Other synonyms of skiagraph include radiogram, radiograph, shadowgraph.

skiagraph (noun)	skiagram (noun)
a photographic image produced on a radiosensitive surface by radiation other than visible light (especially by X-rays or gamma rays)	a photographic image produced on a radiosensitive surface by radiation other than visible light (especially by X-rays or gamma rays)