'Gallic acid' definitions:

Definition of 'gallic acid'

(from WordNet)
noun
A colorless crystalline acid obtained from tannin

Definition of 'Gallic acid'

From: GCIDE
  • Gallic \Gal"lic\ (277), a. [From Gall the excrescence.] Pertaining to, or derived from, galls, nutgalls, and the like. [1913 Webster]
  • Gallic acid (Chem.), an organic acid, very widely distributed in the vegetable kingdom, being found in the free state in galls, tea, etc., and produced artificially. It is a white, crystalline substance, C6H2(HO)3.CO2H, with an astringent taste, and is a strong reducing agent, as employed in photography. It is usually prepared from tannin, and both give a dark color with iron salts, forming tannate and gallate of iron, which are the essential ingredients of common black ink. [1913 Webster]