Signorina vs form of address

Signorina and form of address both are nouns.

Word	Noun	Adjective	Verb	Adverb
Signorina	Yes	No	No	No
form of address	Yes	No	No	No

As nouns, form of address is a hypernym of Signorina; that is, form of address is a word with a broader meaning than Signorina:

Signorina: an Italian title or form of address for an unmarried woman
form of address: an identifying appellation signifying status or function: e.g. `Mr.' or `General'

Other hypernyms of Signorina include title, title of respect.

Signorina (noun)	form of address (noun)
an Italian title or form of address for an unmarried woman	an identifying appellation signifying status or function: e.g. `Mr.' or `General'