potassium nitrate vs saltpeter

potassium nitrate and saltpeter both are nouns.

Word	Noun	Adjective	Verb	Adverb
potassium nitrate	Yes	No	No	No
saltpeter	Yes	No	No	No

As nouns, potassium nitrate and saltpeter are synonyms defined as:

potassium nitrate and saltpeter: (KNO3) used especially as a fertilizer and explosive

Other synonyms of potassium nitrate include niter, nitre, saltpetre.

potassium nitrate (noun)	saltpeter (noun)
(KNO3) used especially as a fertilizer and explosive	(KNO3) used especially as a fertilizer and explosive