cream of tartar vs potassium hydrogen tartrate

cream of tartar and potassium hydrogen tartrate both are nouns.

Word	Noun	Adjective	Verb	Adverb
cream of tartar	Yes	No	No	No
potassium hydrogen tartrate	Yes	No	No	No

As nouns, cream of tartar and potassium hydrogen tartrate are synonyms defined as:

cream of tartar and potassium hydrogen tartrate: a salt used especially in baking powder

Other synonyms of cream of tartar include potassium bitartrate, tartar.

cream of tartar (noun)	potassium hydrogen tartrate (noun)
a salt used especially in baking powder	a salt used especially in baking powder