- See under tannin.
- Chemistry. any of a group of astringent vegetable principles or compounds, chiefly complex glucosides of catechol and pyrogallol, as the reddish compound that gives the tanning properties to oak bark or the whitish compound that occurs in large quantities in nutgalls (common tannin, tannic acid).
- any of these compounds occurring in wine and imparting an astringent taste, especially in red wine.
Origin of tannin
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- any of a class of yellowish or brownish solid compounds found in many plants and used as tanning agents, mordants, medical astringents, etc. Tannins are derivatives of gallic acid with the approximate formula C 76 H 52 O 46Also called: tannic acid
C19: from French tanin, from tan 1
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for common tannin
vegetable substance capable of converting animal hide to leather, 1802, from French tannin (1798), from tan "crushed oak bark containing tannin" (see tan (v.)). Tannic acid first recorded 1836, from French acide tannique, inroduced 1834 by Pelouze.
Online Etymology Dictionary, © 2010 Douglas Harper
- Any of various compounds, including tannic acid, that occur naturally in the bark and fruit of various plants, especially the nutgalls, certain oaks, and sumac. Tannins are polyphenols, and form yellowish to light brown amorphous masses that can be powdery, flaky, or spongy. They bind proteins and are used in dyeing, in tanning leather, in clarifying wine and beer, and as an astringent in medicine. Tannins also give color and flavor to black tea.
- Any of various other substances that promote the tanning of leather, such as chromium salts.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.