double acute accent vs Hungarumlaut

double acute accent and Hungarumlaut both are nouns.

Word	Noun	Adjective	Verb	Adverb
double acute accent	Yes	No	No	No
Hungarumlaut	Yes	No	No	No

As nouns, double acute accent and Hungarumlaut are synonyms defined as:

double acute accent and Hungarumlaut: a diacritic mark of the Latin script, used primarily in written Hungarian.

double acute accent (noun)	Hungarumlaut (noun)
a diacritic mark of the Latin script, used primarily in written Hungarian.	a diacritic mark of the Latin script, used primarily in written Hungarian.