common tannin

WordReference Random House Unabridged Dictionary of American English © 2026

com′mon tan′nin, [Chem.]

1. Chemistry See under tannin. 

WordReference Random House Learner's Dictionary of American English © 2026

tan•nin /ˈtænɪn/   n. [uncountable]

1. Chemistry a chemical used in tanning, found also in tea.

Also called ˈtan•nic ˈac•id. 

WordReference Random House Unabridged Dictionary of American English © 2026

tan•nin  (tan′in), n. 

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. Wine any of these compounds occurring in wine and imparting an astringent taste, esp. in red wine.

• French. See tan¹, -in²
• earlier tanin 1795–1805