tan·nin
noun/ˈtænɪn/
/ˈtænɪn/
(also tannic acid)
[uncountable]- a yellow or brown substance found in the bark of some trees and the fruit of many plants, which is present in wine and tea and used in making leather
单宁；单宁酸；鞣质 Word Originearly 19th cent.: from French tanin, from tan ‘tanbark’ (ultimately related to tan) + -in.