tannic acid vs tannin

tannic acid and tannin both are nouns.

Word	Noun	Adjective	Verb	Adverb
tannic acid	Yes	No	No	No
tannin	Yes	No	No	No

As nouns, tannic acid and tannin are synonyms defined as:

tannic acid and tannin: any of various complex phenolic substances of plant origin; used in tanning and in medicine

tannic acid (noun)	tannin (noun)
any of various complex phenolic substances of plant origin; used in tanning and in medicine	any of various complex phenolic substances of plant origin; used in tanning and in medicine