tannin

Any of various water-soluble polyphenols found in plant tissues that bind proteins and promote the tanning of leather.

Any of various other substances that promote the tanning of leather, such as chromium salts.

Same as tannic acid. Also called taya. See tannic.

Same as Tannic acid, under tannic.

Tannic acid or any of its derivatives.

any of various complex phenolic substances of plant origin; used in tanning and in medicine