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 tan1.
- (chemistry) Tannic acid or any of its derivatives.