Hungarumlaut vs double acute accent

Hungarumlaut and double acute accent both are nouns.

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

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

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

Hungarumlaut (noun)	double acute accent (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.