Also found in: Thesaurus, Medical, Legal, Encyclopedia, Wikipedia.
gal·lic acid(găl′ĭk, gô′lĭk)
A colorless crystalline polyphenol, C7H6O5, derived from certain tannins and used as a tanning agent, as an ink dye, in photography, and in pharmaceuticals.
[French acide gallique, from galle, plant gall; see gall3.]
(Elements & Compounds) a colourless crystalline compound obtained from tannin: used as a tanning agent and in making inks, paper, and pyrogallol; 3,4,5-trihydroxybenzoic acid. Formula: C6H2(OH)3COOH
a white or yellowish solid, C7H6O5, obtained from nutgalls, used esp. in tanning and dyes.
[1785–95; < French]