cablegram vs overseas telegram

cablegram and overseas telegram both are nouns.

Word	Noun	Adjective	Verb	Adverb
cablegram	Yes	No	No	No
overseas telegram	Yes	No	No	No

As nouns, cablegram and overseas telegram are synonyms defined as:

Other synonyms of cablegram include cable.

cablegram (noun)	overseas telegram (noun)
a telegram sent abroad	a telegram sent abroad