Mrs. vs form of address

Mrs. and form of address both are nouns.

Word	Noun	Adjective	Verb	Adverb
Mrs.	Yes	No	No	No
form of address	Yes	No	No	No

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

Mrs.: a form of address for a married woman
form of address: an identifying appellation signifying status or function: e.g. `Mr.' or `General'

Other hypernyms of Mrs. include title, title of respect.

Mrs. (noun)	form of address (noun)
a form of address for a married woman	an identifying appellation signifying status or function: e.g. `Mr.' or `General'