Tannic

[Sarah]

Of or pertaining to tan; derived from, or resembling, tan; as,tannic acid. Tannic acid. (Chem.) (a) An acid obtained from nutgallsas a yellow amorphous substance, C14H10O9, having an astringenttaste, and forming with ferric salts a bluish-black compound, whichis the basis of common ink. Called also tannin, and gallotannic acid.(b) By extension, any one of a series of astringent substancesresembling tannin proper, widely diffused through the vegetablekingdom, as in oak bark, willow, catechu, tea, coffee, etc.