• synonyms


  1. 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).
  2. any of these compounds occurring in wine and imparting an astringent taste, especially in red wine.
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Origin of tannin

1795–1805; earlier tanin < F. See tan1, -in2
Related formsnon·tan·nin, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for tannin

Contemporary Examples

Historical Examples

  • Animal skins also, in any form, uncombined with tannin, may be worked into glue.

  • It is sold in the form of crushed leaves or as a powder (15-20% tannin).

    Vegetable Dyes

    Ethel M. Mairet

  • There is no deception about it: it tastes of tannin and spruce and creosote.

    In the Wilderness

    Charles Dudley Warner

  • The tannin unites with the gelatine; and thus the hide becomes leather.

    Makers of Many Things

    Eva March Tappan

  • It is lots of work to get the tannin out of oak or hemlock bark.

    The Story of Leather

    Sara Ware Bassett

British Dictionary definitions for tannin


  1. 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
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Word Origin

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 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.

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Online Etymology Dictionary, © 2010 Douglas Harper

tannin in Science


  1. 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.
  2. Any of various other substances that promote the tanning of leather, such as chromium salts.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.