What is "gallotannic acid"

Tannic \Tan"nic\, a. Of or pertaining to tan; derived from, or resembling, tan; as, tannic acid. Tannic acid. (Chem.)

1. An acid obtained from nutgalls as a yellow amorphous substance, C14H10O9, having an astringent taste, and forming with ferric salts a bluish-black compound, which is the basis of common ink. Called also tannin, and gallotannic acid.

2. By extension, any one of a series of astringent substances resembling tannin proper, widely diffused through the vegetable kingdom, as in oak bark, willow, catechu, tea, coffee, etc.

n. One of the two forms of tannic acid, found in oak galls.