sanitary towel vs sanitary napkin

sanitary towel and sanitary napkin both are nouns.

Word	Noun	Adjective	Verb	Adverb
sanitary towel	Yes	No	No	No
sanitary napkin	Yes	No	No	No

As nouns, sanitary towel and sanitary napkin are synonyms defined as:

sanitary towel and sanitary napkin: a disposable absorbent pad (trade name Kotex); worn to absorb menstrual flow

Other synonyms of sanitary towel include Kotex.

sanitary towel (noun)	sanitary napkin (noun)
a disposable absorbent pad (trade name Kotex); worn to absorb menstrual flow	a disposable absorbent pad (trade name Kotex); worn to absorb menstrual flow