lady vs ma'am

lady and ma'am both are nouns.

Word	Noun	Adjective	Verb	Adverb
lady	Yes	No	No	No
ma'am	Yes	No	No	No

As nouns, lady and ma'am are synonyms defined as:

Other synonyms of lady include dame, gentlewoman, madam.

lady (noun)	ma'am (noun)
a woman of refinement	a woman of refinement
a polite name for any woman