radiogram vs message

radiogram and message both are nouns.

Word	Noun	Adjective	Verb	Adverb
radiogram	Yes	No	No	No
message	Yes	No	Yes	No

As nouns, message is a hypernym of radiogram; that is, message is a word with a broader meaning than radiogram:

radiogram: a message transmitted by wireless telegraphy
message: a communication (usually brief) that is written or spoken or signaled

radiogram (noun)	message (noun)
a photographic image produced on a radiosensitive surface by radiation other than visible light (especially by X-rays or gamma rays)	content communicating a message; what something is about
a message transmitted by wireless telegraphy	a communication (usually brief) that is written or spoken or signaled