ˈtanə̇n noun
( -s )
Etymology: French tannin, tanin, from tanner to tan hides (from Middle French) + -in — more at tan
1.
a. : gallotannin
b. : any of a group of soluble astringent complex phenolic substances including gallotannin that are widely distributed in plants and are obtained commercially from various sources (as powdered gallnuts, shredded tara, quebracho wood, chestnut wood, wattle, sumac, valonia), that precipitate gelatin and albumin from solution and tan skin and hides, that also precipitate many alkaloids and most basic dyes, that form bluish black or greenish black colors or precipitates with ferric salts, that have been classified on the basis of behavior with acids or enzymes as either hydrolyzable to water-soluble products or as condensed yielding phlobaphenes, and that are used chiefly in tanning, dyeing, and making ink and in medicine as astringents and formerly in the treatment of burns — compare ellagitannin , tea tannin
2. : a substance that has a tanning effect as determined by its adsorption by hide powder : tan 2b