any of a group of naturally occurring phenolic compounds that precipitate proteins, alkaloids, and glucosides from solution, and convert hide into leather, including tannic acid: some are present in coffee and tea
Origin of tanninFrench tanin from tan, tan + -in, -in
- Any of various water-soluble polyphenols found in plant tissues that bind proteins and promote the tanning of leather. Also called tannic acid .
- Any of various other substances that promote the tanning of leather, such as chromium salts.
Origin of tanninFrench from tan crushed oak bark from Old French from Medieval Latin tannum ; see tan 1.
- (chemistry) Tannic acid or any of its derivatives.