Ms vs form of address

Ms and form of address both are nouns.

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

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

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

Other hypernyms of Ms include title, title of respect.

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